Make backup and restore reliable, and keep NFS out of them (0.64.0)

A review of the backup path found several ways a backup was not one, and a
restore could destroy data it did not contain.

Data loss:
- Restore with overwrite rmtree'd the whole stack directory, including
  folders the backup had left out (over 2 GiB, deselected, an NFS share
  mounted inside). It now clears only what the backup holds, keeps the
  excluded paths (recorded in the manifest) and never crosses into another
  filesystem.
- The stack was only stopped when named volumes were selected, so data
  folders inside the stack directory were archived while in use. Any
  selected data now stops it.
- Retention matched by prefix: pruning "app" deleted "app-db"'s backups.
  It now matches backup-<id>-(full|config)-<date>.tar.gz exactly.
- A restore under a new name wrote into the original's volumes when they
  had an explicit name, and into its folders outside the stack directory.
  Both are skipped now; a volume owned by another stack or mounted by a
  running container is never overwritten.
- A truncated archive was only noticed after the old stack was gone. The
  whole archive is verified first, and the stack directory is unpacked
  next to the old one and swapped in.

Remote storage:
- Bind folders on a mounted share (fstab/autofs), bind-type volumes
  pointing at one and shares mounted inside the stack folder are detected
  by filesystem type and not selected; a folder du cannot measure in 20s
  is no longer selected by default either.

Reliability:
- After a backup exactly the containers that ran are started again with
  compose start (falling back to the Docker API), instead of up -d, which
  started services stopped on purpose and applied undeployed edits. A
  stack that cannot be stopped is not backed up.
- Backup and restore hold the stack lock; a scheduled backup that finds
  the stack busy retries after 10 minutes. Restore stops the stack while
  replacing its data and brings it back up.
- external: true volumes are backed up; anonymous ones are listed, not
  selected. Restored volumes get their original driver and options.
- A backup with uncaptured data or a stack that did not restart is
  reported as incomplete: in the dialog, and for schedules as a warning
  with a notification and without rotating older backups out.
- Archive writing and restore run off the event loop; downloads delete
  their temp file; helper containers use the long-timeout client; S3
  listing is paginated; a file changing mid-read no longer corrupts the
  archive.

Manifest format 3 records compose_binds/excluded and volume
driver/options/external; format 1/2 backups still restore.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

@@ -590,6 +590,35 @@ it is what your saved destination credentials are encrypted with.
   folders back at their host paths and preserves permissions, ownership and
   symlinks (PUID/PGID-based images such as the *arr suite need this), with
   optional rename and overwrite/conflict detection.
+
+  **How backup and restore stay reliable** (0.64.0):
+  - The stack's running containers are stopped whenever any data is captured —
+    also when the data is only folders inside the stack directory — and exactly
+    those are started again (`compose start`, not `up`, so services you stopped
+    stay stopped and undeployed compose edits are not applied). A stack that
+    cannot be stopped is not backed up. The stack is locked meanwhile, so a
+    deploy, update or scheduled backup cannot interleave (a scheduled backup
+    that finds the stack busy retries after 10 minutes).
+  - Remote storage is kept out by what it *is*, not only by how it is declared:
+    NFS/CIFS volumes, bind folders on a mounted share (`/mnt/nas/…` via fstab or
+    autofs), bind-type volumes pointing at one, and shares mounted inside the
+    stack folder. Folders too big to measure in 20 s are not selected either.
+  - Volumes the stack uses without owning them (`external: true`) are backed up
+    too; anonymous volumes are listed but not selected.
+  - Restore reads the whole archive first and refuses a damaged one before
+    touching anything, stops the stack while replacing its data, unpacks the
+    stack folder next to the old one and then swaps it in. With *Overwrite*,
+    folders the backup left out (too large, deselected, remote) and other
+    filesystems mounted inside the stack folder are **kept**, not deleted.
+  - Restoring under a new name never writes into the original stack: folders
+    outside the stack directory and volumes not named after the stack are
+    skipped, and a volume owned by another stack or mounted by a running
+    container is never overwritten. Missing volumes are recreated with their
+    original driver and options.
+  - A backup that could not capture everything, or left the stack down, is
+    reported as incomplete — in the dialog and for scheduled backups, which
+    then notify and do not rotate out older backups. Retention only matches
+    the stack's own files (it used to take `app-db`'s backups for `app`).
 - **Notification webhooks**: ntfy, Discord, Slack, Gotify, or generic JSON, each
   subscribed to chosen events (image update available, stack start/stop/error,
   pull failed). Managed in **Settings → Notifications**; env `NOTIFY_WEBHOOKS`

backend/routers/backups.py

@@ -8,6 +8,7 @@ import tempfile
 
 from fastapi import APIRouter, Depends, File, Form, HTTPException, Query, Request, UploadFile
 from fastapi.responses import FileResponse
+from starlette.background import BackgroundTask
 from pydantic import BaseModel
 from sqlmodel import Session
 
@@ -41,15 +42,32 @@ def _compact(report: dict) -> dict:
         "volumes": report.get("volumes", []),
         "skipped": report.get("skipped", []),
         "path_mismatch": report.get("path_mismatch"),
+        "stopped": report.get("stopped", []),
+        "errors": report.get("errors", []),
+        # Capped: a busy log folder can produce a warning per file, and this
+        # travels in a response header for downloads.
+        "warnings": report.get("warnings", [])[:20],
+        "restart_error": report.get("restart_error"),
     }
 
 
 def _summary(report: dict) -> str:
-    return (
+    text = (
         f"binds={len(report.get('binds', []))} "
         f"volumes={len(report.get('volumes', []))} "
         f"skipped={len(report.get('skipped', []))}"
     )
+    if report.get("errors"):
+        text += f" errors={len(report['errors'])}"
+    if report.get("restart_error"):
+        text += " restart_failed"
+    return text
+
+
+def _backup_http_error(exc: backup_service.BackupError) -> HTTPException:
+    # 409 for a stack that is busy or already exists, 400 for the rest.
+    conflict = isinstance(exc, backup_service.StackBusyError) or "already exists" in str(exc)
+    return HTTPException(status_code=409 if conflict else 400, detail=str(exc))
 
 
 @router.get("/{stack_id}/backup/inventory")
@@ -88,7 +106,7 @@ async def backup_stack(
             binds=binds, volumes=volumes,
         )
     except backup_service.BackupError as exc:
-        raise HTTPException(status_code=400, detail=str(exc)) from exc
+        raise _backup_http_error(exc) from exc
     audit_service.record(
         session, user=user.username, action="stack.backup", target=stack_id,
         detail=_summary(report), ip=_ip(request),
@@ -100,6 +118,9 @@ async def backup_stack(
         # The browser downloads a blob, so the summary of what actually made it
         # into the archive rides along in a header.
         headers={"X-Stackpilot-Backup": json.dumps(_compact(report))},
+        # The archive is a temp file; without this every download stayed in
+        # the container's /tmp until it filled the disk.
+        background=BackgroundTask(os.unlink, path),
     )
 
 
@@ -122,7 +143,7 @@ async def restore_stack(
 
         target = compose_service.slugify(target_id) if target_id else None
         try:
-            result = backup_service.restore_backup(
+            result = await backup_service.restore(
                 tmp.name,
                 target_id=target,
                 overwrite=overwrite,
@@ -130,9 +151,7 @@ async def restore_stack(
                 restore_binds=restore_binds,
             )
         except backup_service.BackupError as exc:
-            # 409 for the "already exists" conflict, 400 for malformed backups.
+            raise _backup_http_error(exc) from exc
-            code = 409 if "already exists" in str(exc) else 400
-            raise HTTPException(status_code=code, detail=str(exc)) from exc
 
         stack_id = result["stack_id"]
         stack = session.get(Stack, stack_id)
@@ -199,7 +218,7 @@ async def push_backup(
             include_binds=body.include_binds, binds=body.binds, volumes=body.volumes,
         )
     except backup_service.BackupError as exc:
-        raise HTTPException(status_code=400, detail=str(exc)) from exc
+        raise _backup_http_error(exc) from exc
 
     filename = _backup_filename(stack_id, body.include_volumes)
     try:
@@ -238,14 +257,13 @@ async def restore_from_destination(
 
         target = compose_service.slugify(body.target_id) if body.target_id else None
         try:
-            result = backup_service.restore_backup(
+            result = await backup_service.restore(
                 tmp.name, target_id=target,
                 overwrite=body.overwrite, restore_volumes=body.restore_volumes,
                 restore_binds=body.restore_binds,
             )
         except backup_service.BackupError as exc:
-            code = 409 if "already exists" in str(exc) else 400
+            raise _backup_http_error(exc) from exc
-            raise HTTPException(status_code=code, detail=str(exc)) from exc
 
         stack_id = result["stack_id"]
         if not session.get(Stack, stack_id):

backend/services/backup_destination_service.py

@@ -219,11 +219,14 @@ def _s3_list(cfg: dict) -> list[dict]:
     if prefix:
         kwargs["Prefix"] = prefix + "/"
     try:
-        resp = client.list_objects_v2(**kwargs)
+        # Paginated: one call returns at most 1000 keys, and retention sorts
+        # by age, so the oldest backups were the ones it never saw.
+        pages = client.get_paginator("list_objects_v2").paginate(**kwargs)
+        objects = [obj for page in pages for obj in page.get("Contents", [])]
     except Exception as exc:  # noqa: BLE001
         raise DestinationError(f"S3 list failed: {exc}") from exc
     out = []
-    for obj in resp.get("Contents", []):
+    for obj in objects:
         name = obj["Key"].split("/")[-1]
         if not name.endswith(".tar.gz"):
             continue

backend/services/compose_service.py

@@ -127,6 +127,10 @@ def discover_stacks(override: Optional[str] = None) -> list[str]:
         return []
     found = []
     for entry in sorted(os.listdir(root)):
+        # Hidden directories are StackPilot's own scratch space (a restore
+        # stages there before swapping it in), never a stack.
+        if entry.startswith("."):
+            continue
         directory = os.path.join(root, entry)
         if os.path.isdir(directory) and find_compose_file(directory):
             found.append(entry)

backend/services/schedule_service.py

@@ -28,6 +28,10 @@ from services import (
 
 logger = logging.getLogger("stackpilot.schedule")
 
+#: A stack that is busy (deploying, updating) when its backup is due is tried
+#: again this much later instead of waiting for the next regular run.
+BUSY_RETRY = timedelta(minutes=10)
+
 
 def _now() -> datetime:
     return datetime.now(timezone.utc).replace(tzinfo=None)
@@ -57,11 +61,12 @@ def compute_next_run(
     return base
 
 
-def _prune(dest: BackupDestination, basename: str, keep: int) -> int:
+def _prune(dest: BackupDestination, stack_id: str, keep: int) -> int:
     if keep <= 0:
         return 0
     items = dest_service.list_backups(dest)
-    mine = [i for i in items if i["name"].startswith(f"{basename}-")]
+    pattern = backup_service.backup_name_pattern(stack_id)
+    mine = [i for i in items if pattern.match(i["name"])]
     mine.sort(key=lambda x: x.get("modified") or 0, reverse=True)
     removed = 0
     for old in mine[keep:]:
@@ -73,12 +78,28 @@ def _prune(dest: BackupDestination, basename: str, keep: int) -> int:
     return removed
 
 
+def _problems(report: dict) -> list[str]:
+    """What makes a backup that was written less than a success."""
+    problems = [f"not captured: {e}" for e in report.get("errors") or []]
+    if report.get("restart_error"):
+        problems.append(f"stack did not start again: {report['restart_error']}")
+    return problems
+
+
+async def _alert(session: Session, title: str, body: str) -> None:
+    try:
+        await notify_service.notify(EVENT_BACKUP_FAILED, title, body, session)
+    except Exception:  # noqa: BLE001
+        pass
+
+
 async def run_schedule(session: Session, schedule: BackupSchedule) -> dict:
     """Execute one schedule now. Updates status + next_run. Returns a summary."""
     now = _now()
     dest = session.get(BackupDestination, schedule.destination_id)
     result: dict = {"ok": False}
     path = None
+    next_run = None
     try:
         if not dest:
             raise RuntimeError(f"destination {schedule.destination_id} not found")
@@ -86,36 +107,50 @@ async def run_schedule(session: Session, schedule: BackupSchedule) -> dict:
         stack = session.get(Stack, schedule.stack_id)
         if not stack:
             raise RuntimeError(f"stack '{schedule.stack_id}' not found")
-        path = await backup_service.create_backup(
+        path, report = await backup_service.create_backup_ex(
             schedule.stack_id, stack.name,
             include_volumes=schedule.include_volumes, stop_first=schedule.stop_first,
         )
 
         filename = backup_service.backup_filename(schedule.stack_id, schedule.include_volumes)
-        basename = backup_service.backup_basename(schedule.stack_id)
         await asyncio.to_thread(dest_service.upload, dest, path, filename)
-        pruned = await asyncio.to_thread(_prune, dest, basename, schedule.keep)
+        problems = _problems(report)
-        schedule.last_status = "ok"
+        # Retention only after a complete backup: an incomplete one must not
-        result = {"ok": True, "name": filename, "destination": dest.name, "pruned": pruned}
+        # push the last good backup out.
-        logger.info("Scheduled backup %s → %s ok (pruned %d)", schedule.stack_id, dest.name, pruned)
+        pruned = 0 if problems else await asyncio.to_thread(
+            _prune, dest, schedule.stack_id, schedule.keep
+        )
+        result = {"ok": not problems, "name": filename, "destination": dest.name, "pruned": pruned}
+        if problems:
+            schedule.last_status = f"warning: {'; '.join(problems)}"[:300]
+            result["error"] = "; ".join(problems)
+            logger.warning("Scheduled backup %s incomplete: %s", schedule.stack_id, problems)
+            await _alert(
+                session,
+                f"Scheduled backup of '{schedule.stack_id}' is incomplete",
+                "\n".join(problems),
+            )
+        else:
+            schedule.last_status = "ok"
+            logger.info(
+                "Scheduled backup %s → %s ok (pruned %d)", schedule.stack_id, dest.name, pruned
+            )
+    except backup_service.StackBusyError as exc:
+        # Deploys and updates are short: try again soon rather than skipping a day.
+        schedule.last_status = f"retrying: {exc}"[:300]
+        result = {"ok": False, "error": str(exc)}
+        next_run = now + BUSY_RETRY
+        logger.info("Scheduled backup %s postponed: %s", schedule.stack_id, exc)
     except Exception as exc:  # noqa: BLE001
         schedule.last_status = f"error: {exc}"[:300]
         result = {"ok": False, "error": str(exc)}
         logger.warning("Scheduled backup %s failed: %s", schedule.stack_id, exc)
-        try:
+        await _alert(session, f"Scheduled backup of '{schedule.stack_id}' failed", str(exc))
-            await notify_service.notify(
-                EVENT_BACKUP_FAILED,
-                f"Scheduled backup of '{schedule.stack_id}' failed",
-                str(exc),
-                session,
-            )
-        except Exception:  # noqa: BLE001
-            pass
     finally:
         if path and os.path.exists(path):
             os.unlink(path)
         schedule.last_run = now
-        schedule.next_run = compute_next_run(
+        schedule.next_run = next_run or compute_next_run(
             schedule.frequency, schedule.hour, schedule.minute, schedule.weekday, now
         )
         session.add(schedule)

backend/services/stack_assets_service.py

@@ -24,7 +24,7 @@ from typing import Optional
 import yaml
 
 from config import settings
-from docker_client import DockerError, get_client, safe_call
+from docker_client import DockerError, get_client, get_long_client, safe_call
 from services import compose_service
 
 logger = logging.getLogger("stackpilot.assets")
@@ -49,6 +49,24 @@ SYSTEM_PREFIXES = ("/dev", "/proc", "/sys", "/run", "/var/run", "/var/lib/docker
 # user wants, and *restoring* one would overwrite the share.
 REMOTE_VOLUME_TYPES = {"nfs", "nfs4", "cifs", "smb", "smb3", "smbfs", "sshfs", "glusterfs"}
 
+# The same for bind mounts and bind-type volumes, which only say *where* they
+# are, not what: a host directory can be an NFS mount (fstab/autofs) just as
+# well. Recognised by the filesystem magic `stat -f` reports for the path.
+REMOTE_FS_MAGIC = {
+    0x6969: "nfs",
+    0x517B: "smb",
+    0xFF534D42: "cifs",
+    0xFE534D42: "smb2",
+    0x00C36400: "ceph",
+}
+# Mount types in /proc/self/mountinfo that are remote storage.
+REMOTE_MOUNT_TYPES = {"nfs", "nfs4", "cifs", "smb3", "smbfs", "ceph", "glusterfs",
+                      "fuse.sshfs", "fuse.rclone", "fuse.glusterfs"}
+
+# Volumes Docker names itself (64 hex chars): recreated with every container, so
+# a restore could never hand them back to the service.
+_ANONYMOUS_RE = re.compile(r"^[0-9a-f]{64}$")
+
 # Bind directories larger than this are listed but not selected by default.
 DEFAULT_MAX_BIND_BYTES = 2 * 1024**3
 
@@ -116,7 +134,7 @@ def _put_archive(container, dest: str, src_file: str, volumes: dict) -> None:
             if not _is_chown_error(exc):
                 raise
     logger.warning("%s rejects ownership changes; restoring without it", dest)
-    client = get_client()
+    client = get_long_client()
     staging = _create_helper_with(
         client, volumes, ["sh", "-c", f"cp -R /tmp/. '{dest}/'"]
     )
@@ -142,26 +160,35 @@ def _create_helper_with(client, volumes: dict, command: list[str]):
     )
 
 
-def inspect_paths(paths: list[str]) -> dict[str, dict]:
+def _unknown() -> dict:
-    """Classify host paths ({path: {"kind", "size"}}) via one helper container.
+    return {"kind": "unknown", "size": None, "fs": None, "remote": None, "measured": False}
 
-    ``kind`` is dir / file / special; ``size`` is bytes (best effort, the walk is
+
-    capped so a huge media share can't stall the request).
+def inspect_paths(paths: list[str]) -> dict[str, dict]:
+    """Classify host paths via one helper container.
+
+    ``{path: {"kind", "size", "fs", "remote", "measured"}}``: ``kind`` is dir /
+    file / special, ``size`` bytes. ``remote`` names the network filesystem the
+    path sits on (nfs, cifs, ...), whose contents are not walked at all.
+    Directory sizes are capped at 20s of ``du``; ``measured`` is False when that
+    ran out, which on its own says the directory is big.
     """
     unique = [p for p in dict.fromkeys(paths) if p]
     if not unique:
         return {}
-    client = get_client()
+    client = get_long_client()
     ensure_helper_image(client)
     mounts = {p: {"bind": f"/m/{i}", "mode": "ro"} for i, p in enumerate(unique)}
+    remote_hex = "|".join(f"{m:x}" for m in REMOTE_FS_MAGIC)
     script_parts = []
     for i in range(len(unique)):
         script_parts.append(
-            f'd=/m/{i}; '
+            f'd=/m/{i}; t=$(stat -f -c %t "$d" 2>/dev/null); t=${{t:--}}; '
-            f'if [ -d "$d" ]; then s=$(timeout 20 du -sk "$d" 2>/dev/null | cut -f1); '
+            f'if [ -d "$d" ]; then '
-            f'echo "{i} dir ${{s:-}}"; '
+            f'case "$t" in {remote_hex}) echo "{i} dir - $t";; '
-            f'elif [ -f "$d" ]; then echo "{i} file $(stat -c %s "$d" 2>/dev/null)"; '
+            f'*) s=$(timeout 20 du -sk "$d" 2>/dev/null | cut -f1); echo "{i} dir ${{s:--}} $t";; esac; '
-            f'else echo "{i} special"; fi'
+            f'elif [ -f "$d" ]; then echo "{i} file $(stat -c %s "$d" 2>/dev/null) $t"; '
+            f'else echo "{i} special - $t"; fi'
         )
     script = "; ".join(script_parts)
     try:
@@ -176,9 +203,9 @@ def inspect_paths(paths: list[str]) -> dict[str, dict]:
         )
     except DockerError as exc:
         logger.warning("Path inspection failed: %s", exc)
-        return {p: {"kind": "unknown", "size": None} for p in unique}
+        return {p: _unknown() for p in unique}
 
-    result: dict[str, dict] = {p: {"kind": "unknown", "size": None} for p in unique}
+    result: dict[str, dict] = {p: _unknown() for p in unique}
     for line in (out or b"").decode("utf-8", "replace").splitlines():
         parts = line.strip().split()
         if len(parts) < 2 or not parts[0].isdigit():
@@ -190,13 +217,24 @@ def inspect_paths(paths: list[str]) -> dict[str, dict]:
         size: Optional[int] = None
         if len(parts) > 2 and parts[2].isdigit():
             size = int(parts[2]) * 1024 if kind == "dir" else int(parts[2])
-        result[unique[idx]] = {"kind": kind, "size": size}
+        fs = parts[3] if len(parts) > 3 and parts[3] != "-" else None
+        try:
+            remote = REMOTE_FS_MAGIC.get(int(fs, 16)) if fs else None
+        except ValueError:
+            remote = None
+        result[unique[idx]] = {
+            "kind": kind,
+            "size": size,
+            "fs": fs,
+            "remote": remote,
+            "measured": kind != "dir" or remote is not None or size is not None,
+        }
     return result
 
 
 def export_path(source: str, kind: str, dest_file: str) -> int:
     """Tar a host path (dir contents, or a single file) into ``dest_file``."""
-    client = get_client()
+    client = get_long_client()
     ensure_helper_image(client)
     if kind == "file":
         parent, base = _split(source)
@@ -223,7 +261,7 @@ def export_path(source: str, kind: str, dest_file: str) -> int:
 
 def import_path(source: str, kind: str, src_file: str) -> None:
     """Unpack an archive produced by :func:`export_path` back to its host path."""
-    client = get_client()
+    client = get_long_client()
     ensure_helper_image(client)
     if kind == "file":
         parent, _base = _split(source)
@@ -239,7 +277,7 @@ def import_path(source: str, kind: str, src_file: str) -> None:
 
 def export_volume(full_name: str, dest_file: str) -> int:
     """Stream a named volume's contents into ``dest_file`` (never into RAM)."""
-    client = get_client()
+    client = get_long_client()
     ensure_helper_image(client)
     container = _create_helper(client, {full_name: {"bind": "/v", "mode": "ro"}})
     written = 0
@@ -254,16 +292,53 @@ def export_volume(full_name: str, dest_file: str) -> int:
     return written
 
 
-def import_volume(full_name: str, labels: dict, src_file: str, wipe: bool = True) -> None:
+def volume_attrs(full_name: str) -> Optional[dict]:
-    """Restore a volume from an archive, optionally clearing it first."""
+    """A volume's inspect data, or None if it does not exist."""
-    client = get_client()
+    try:
+        return safe_call(get_client().volumes.get, full_name).attrs or {}
+    except DockerError:
+        return None
+
+
+def running_users(full_name: str) -> list[str]:
+    """Names of running containers that have the volume mounted."""
+    try:
+        containers = safe_call(
+            get_client().containers.list, filters={"volume": full_name, "status": "running"}
+        )
+    except DockerError:
+        return []
+    return sorted(c.name for c in containers)
+
+
+def import_volume(
+    full_name: str,
+    labels: dict,
+    src_file: str,
+    wipe: bool = True,
+    driver: Optional[str] = None,
+    driver_opts: Optional[dict] = None,
+) -> None:
+    """Restore a volume from an archive, optionally clearing it first.
+
+    A missing volume is recreated with the driver and options it had, not as a
+    plain local volume: compose refuses to use an existing volume whose
+    configuration differs from the compose file.
+    """
+    client = get_long_client()
     ensure_helper_image(client)
     existed = True
     try:
         safe_call(client.volumes.get, full_name)
     except DockerError:
         existed = False
-        safe_call(client.volumes.create, name=full_name, labels=labels or {})
+        safe_call(
+            client.volumes.create,
+            name=full_name,
+            driver=driver or "local",
+            driver_opts=driver_opts or None,
+            labels=labels or {},
+        )
     if existed and wipe:
         # Restore means "back to the snapshot": drop files created since.
         safe_call(
@@ -429,8 +504,77 @@ def _inside(path: str, parent: str) -> bool:
     return path == parent or path.startswith(parent + "/")
 
 
+def _volume_entry(name: str, attrs: dict, external: bool) -> dict:
+    labels = attrs.get("Labels") or {}
+    options = attrs.get("Options") or {}
+    driver = attrs.get("Driver", "local")
+    vtype = str(options.get("type") or "").lower()
+    device = str(options.get("device") or "")
+    remote = (
+        vtype in REMOTE_VOLUME_TYPES
+        or driver != "local"
+        or device.startswith("//")
+        or device.startswith(":")
+    )
+    # A local volume that binds a host directory (type none, o=bind) is only as
+    # local as that directory; inventory() checks what it sits on.
+    bind_device = (
+        device
+        if not remote and device.startswith("/") and "bind" in str(options.get("o") or "")
+        else None
+    )
+    return {
+        "name": name,
+        "short": labels.get(COMPOSE_VOLUME_LABEL, name),
+        "labels": labels,
+        "driver": driver,
+        "options": options,
+        "remote": remote,
+        "remote_type": vtype or (driver if driver != "local" else None),
+        "external": external,
+        "bind_device": bind_device,
+    }
+
+
+def _external_volume_names(stack_id: str) -> set[str]:
+    """Named volumes the stack uses but compose did not create for it:
+    ``external: true`` in the compose file, or mounted by its containers."""
+    names: set[str] = set()
+    try:
+        client = get_client()
+        containers = safe_call(
+            client.containers.list,
+            all=True,
+            filters={"label": f"{COMPOSE_PROJECT_LABEL}={stack_id}"},
+        )
+        for c in containers:
+            for mount in c.attrs.get("Mounts") or []:
+                if mount.get("Type") == "volume" and mount.get("Name"):
+                    names.add(mount["Name"])
+    except DockerError:
+        pass
+    compose_file = compose_service.find_compose_file(compose_service.stack_dir(stack_id))
+    if compose_file:
+        try:
+            with open(compose_file, "r", encoding="utf-8", errors="replace") as fh:
+                data = yaml.safe_load(fh) or {}
+        except (OSError, yaml.YAMLError):
+            data = {}
+        env = _env_for_stack(stack_id)
+        for key, spec in (data.get("volumes") or {}).items():
+            if isinstance(spec, dict) and spec.get("external"):
+                names.add(_interpolate(str(spec.get("name") or key), env))
+    return names
+
+
 def compose_volumes(stack_id: str) -> list[dict]:
-    """Compose-managed named volumes, with remote-storage detection."""
+    """The stack's named volumes, with remote-storage detection.
+
+    Compose-created ones carry the project label. Volumes the stack only uses
+    (``external: true``, or created by hand) do not, and were silently missing
+    from backups before; they are listed with ``external`` set. Anonymous
+    volumes are listed too, so it is visible that data lives in one.
+    """
     try:
         client = get_client()
         vols = safe_call(
@@ -439,34 +583,43 @@ def compose_volumes(stack_id: str) -> list[dict]:
         )
     except DockerError:
         return []
-    out = []
+    out = [_volume_entry(v.name, v.attrs or {}, external=False) for v in vols]
-    for v in vols:
+    known = {v["name"] for v in out}
-        attrs = v.attrs or {}
+    for name in sorted(_external_volume_names(stack_id) - known):
-        labels = attrs.get("Labels") or {}
+        attrs = volume_attrs(name)
-        options = attrs.get("Options") or {}
+        if attrs is None:
-        driver = attrs.get("Driver", "local")
+            continue  # declared external but not created yet
-        vtype = str(options.get("type") or "").lower()
+        out.append(_volume_entry(name, attrs, external=True))
-        device = str(options.get("device") or "")
-        remote = (
-            vtype in REMOTE_VOLUME_TYPES
-            or driver != "local"
-            or device.startswith("//")
-            or device.startswith(":")
-        )
-        out.append(
-            {
-                "name": v.name,
-                "short": labels.get(COMPOSE_VOLUME_LABEL, v.name),
-                "labels": labels,
-                "driver": driver,
-                "options": options,
-                "remote": remote,
-                "remote_type": vtype or (driver if driver != "local" else None),
-            }
-        )
     return out
 
 
+def _mounts() -> list[tuple[str, str]]:
+    """(mount point, filesystem type) of every mount this process sees."""
+    out = []
+    try:
+        with open("/proc/self/mountinfo", "r", encoding="utf-8") as fh:
+            for line in fh:
+                left, _, right = line.partition(" - ")
+                fields, rfields = left.split(), right.split()
+                if len(fields) >= 5 and rfields:
+                    # Spaces etc. are octal-escaped in mountinfo.
+                    point = fields[4].encode().decode("unicode_escape")
+                    out.append((point, rfields[0]))
+    except OSError:
+        pass
+    return out
+
+
+def remote_mount_type(path: str) -> Optional[str]:
+    """The remote filesystem type ``path`` lives on as this process sees it,
+    e.g. an NFS share mounted inside the stacks directory. None if local."""
+    best, best_type = "", None
+    for point, fstype in _mounts():
+        if _inside(path, point) and len(point) >= len(best):
+            best, best_type = point, fstype
+    return best_type if best_type in REMOTE_MOUNT_TYPES else None
+
+
 def inventory(stack_id: str, max_bind_bytes: int = DEFAULT_MAX_BIND_BYTES) -> dict:
     """What a backup of this stack would (and would not) capture.
 
@@ -488,14 +641,18 @@ def inventory(stack_id: str, max_bind_bytes: int = DEFAULT_MAX_BIND_BYTES) -> di
         if mount not in entry["mounts"]:
             entry["mounts"].append(mount)
 
+    volumes_raw = compose_volumes(stack_id)
     real_paths = [p for p in grouped if not is_system_path(p)]
-    stats = inspect_paths(real_paths)
+    stats = inspect_paths(
+        real_paths + [v["bind_device"] for v in volumes_raw if v["bind_device"]]
+    )
 
     binds = []
     for path, entry in sorted(grouped.items()):
         system = is_system_path(path)
-        info = stats.get(path, {"kind": "unknown", "size": None})
+        info = stats.get(path) or _unknown()
         kind, size = info["kind"], info["size"]
+        remote = info.get("remote") or (remote_mount_type(path) if not system else None)
         inside = _inside(path, directory)
         # A path inside the stack directory that this process can actually read
         # is already covered by the compose/ tree in the archive.
@@ -504,12 +661,17 @@ def inventory(stack_id: str, max_bind_bytes: int = DEFAULT_MAX_BIND_BYTES) -> di
         reason = None
         if system:
             include, reason = False, "system path"
+        elif remote:
+            include, reason = False, f"remote storage ({remote})"
         elif kind == "special":
             include, reason = False, "not a regular file or directory"
         elif kind == "unknown":
             include, reason = False, "could not inspect path"
         elif size is not None and size > max_bind_bytes:
             include, reason = False, f"larger than {max_bind_bytes // 1024**3} GiB"
+        elif not info.get("measured", True):
+            # du ran out of time: too big to have been walked in 20s.
+            include, reason = False, "too large to measure"
         binds.append(
             {
                 "source": path,
@@ -522,21 +684,24 @@ def inventory(stack_id: str, max_bind_bytes: int = DEFAULT_MAX_BIND_BYTES) -> di
                 "covered_by_compose": visible,
                 "via": "compose" if visible else "archive",
                 "system": system,
+                "remote": remote,
                 "include_default": include,
                 "reason": reason,
             }
         )
 
     volumes = []
-    for vol in compose_volumes(stack_id):
+    for vol in volumes_raw:
-        include = not vol["remote"]
+        if vol["bind_device"]:
-        volumes.append(
+            device_remote = (stats.get(vol["bind_device"]) or {}).get("remote")
-            {
+            if device_remote:
-                **vol,
+                vol = {**vol, "remote": True, "remote_type": device_remote}
-                "include_default": include,
+        include, reason = True, None
-                "reason": None if include else f"remote storage ({vol['remote_type']})",
+        if vol["remote"]:
-            }
+            include, reason = False, f"remote storage ({vol['remote_type']})"
-        )
+        elif _ANONYMOUS_RE.match(vol["name"]):
+            include, reason = False, "anonymous volume (Docker recreates it with the container)"
+        volumes.append({**vol, "include_default": include, "reason": reason})
 
     return {
         "stack_id": stack_id,

backend/tests/test_backup_restore.py

@@ -0,0 +1,817 @@
+"""Backup and restore, end to end on real files and real archives.
+
+Docker is faked (containers, volumes, the helper container); everything that
+touches the stack directory and the archive runs for real. The cases are the
+ways a backup used to fail to be one:
+
+* data folders inside the stack directory were archived while the stack kept
+  writing to them (it was only stopped when named volumes were selected);
+* the stack came back with ``up -d`` — starting services that had been
+  stopped on purpose and applying undeployed compose edits;
+* a restore with "overwrite" deleted the whole stack directory, including the
+  folders the backup had left out (too large, deselected, NFS);
+* a truncated archive was only noticed after the old stack was gone;
+* a restore under a new name overwrote the original stack's volumes;
+* retention for stack "app" deleted the backups of stack "app-db";
+* a backup with a failed volume was reported as "ok".
+"""
+from __future__ import annotations
+
+import asyncio
+import gzip
+import io
+import json
+import os
+import tarfile
+import uuid
+
+import pytest
+
+from services import backup_service, compose_service, stack_assets_service as assets
+from services.compose_service import ContainerInfo
+
+
+# --------------------------------------------------------------------------- #
+# Fakes
+# --------------------------------------------------------------------------- #
+
+
+class FakeDocker:
+    """Records what the backup asked Docker/compose to do."""
+
+    def __init__(self):
+        self.containers: list[ContainerInfo] = []
+        self.compose_calls: list[list[str]] = []
+        self.compose_fail: set[str] = set()
+        self.volumes: dict[str, dict] = {}  # name -> {"files": {...}, "labels", ...}
+        self.running_users: dict[str, list[str]] = {}
+        self.imported: list[dict] = []
+        self.export_fail: set[str] = set()
+
+    def container(self, service: str, state: str = "running") -> ContainerInfo:
+        c = ContainerInfo(
+            id=f"id-{service}", name=f"x-{service}-1", service=service,
+            image="img", state=state, status=state,
+        )
+        self.containers.append(c)
+        return c
+
+    # compose_service
+    def containers_for_stack(self, stack_id):
+        return list(self.containers)
+
+    async def run_compose(self, stack_id, args, override=None, timeout=600.0):
+        self.compose_calls.append(list(args))
+        failed = args[0] in self.compose_fail
+        if not failed and args[0] == "stop":
+            for c in self.containers:
+                if c.service in args[1:]:
+                    c.state = "exited"
+        if not failed and args[0] in ("start", "up"):
+            for c in self.containers:
+                if args[0] == "up" or c.service in args[1:]:
+                    c.state = "running"
+        return {
+            "returncode": 1 if failed else 0,
+            "stdout": "",
+            "stderr": f"{args[0]} failed" if failed else "",
+            "command": " ".join(args),
+        }
+
+    # stack_assets_service
+    def export_volume(self, name, dest_file):
+        if name in self.export_fail:
+            raise RuntimeError("helper container could not mount the volume")
+        with tarfile.open(dest_file, "w") as tar:
+            for rel, content in self.volumes[name]["files"].items():
+                info = tarfile.TarInfo(rel)
+                info.size = len(content)
+                tar.addfile(info, io.BytesIO(content))
+        return os.path.getsize(dest_file)
+
+    def import_volume(self, name, labels, src_file, wipe=True, driver=None, driver_opts=None):
+        with tarfile.open(src_file) as tar:
+            files = {m.name: tar.extractfile(m).read() for m in tar.getmembers() if m.isreg()}
+        self.imported.append(
+            {"name": name, "labels": labels, "wipe": wipe, "driver": driver,
+             "driver_opts": driver_opts, "files": files}
+        )
+        self.volumes[name] = {"files": files, "labels": labels}
+
+    def volume_attrs(self, name):
+        vol = self.volumes.get(name)
+        return None if vol is None else {"Labels": vol.get("labels") or {}}
+
+
+@pytest.fixture
+def docker(monkeypatch, db):
+    fake = FakeDocker()
+    monkeypatch.setattr(compose_service, "containers_for_stack", fake.containers_for_stack)
+    monkeypatch.setattr(compose_service, "run_compose", fake.run_compose)
+    monkeypatch.setattr(assets, "export_volume", fake.export_volume)
+    monkeypatch.setattr(assets, "import_volume", fake.import_volume)
+    monkeypatch.setattr(assets, "volume_attrs", fake.volume_attrs)
+    monkeypatch.setattr(assets, "running_users", lambda name: fake.running_users.get(name, []))
+
+    def no_docker(ids, action):
+        raise RuntimeError("docker unavailable")
+
+    monkeypatch.setattr(backup_service, "_docker_each", no_docker)
+    return fake
+
+
+def _bind(source, directory, size=1024, include=True, reason=None, via="compose"):
+    inside = source == directory or source.startswith(directory + "/")
+    return {
+        "source": source, "mounts": [{"service": "app", "target": "/data"}],
+        "kind": "dir", "size": size, "inside_stack_dir": inside,
+        "covered_by_compose": via == "compose", "via": via, "system": False,
+        "remote": None, "include_default": include, "reason": reason,
+    }
+
+
+def _volume(name, stack_id, include=True, reason=None, external=False, remote=False):
+    labels = {} if external else {
+        assets.COMPOSE_PROJECT_LABEL: stack_id,
+        assets.COMPOSE_VOLUME_LABEL: name.split("_", 1)[-1],
+    }
+    return {
+        "name": name, "short": name.split("_", 1)[-1], "labels": labels,
+        "driver": "local", "options": {"type": "none", "o": "bind", "device": "/srv/x"} if remote else {},
+        "remote": remote, "remote_type": "nfs" if remote else None,
+        "external": external, "bind_device": None,
+        "include_default": include, "reason": reason,
+    }
+
+
+@pytest.fixture
+def stack(monkeypatch, docker):
+    """A stack laid out the way the user keeps them: compose, .env and data
+    folders side by side in /opt/stacks/<stack>."""
+    stack_id = f"s{uuid.uuid4().hex[:8]}"
+    directory = compose_service.stack_dir(stack_id)
+    os.makedirs(os.path.join(directory, "config"))
+    os.makedirs(os.path.join(directory, "media", "movies"))
+    _write(directory, "compose.yaml", "services:\n  app:\n    image: img\n")
+    _write(directory, ".env", "PASSWORD=hunter2\n")
+    _write(directory, "config/app.db", "state-at-backup")
+    _write(directory, "media/movies/big.mkv", "x" * 100)
+
+    inv = {
+        "stack_id": stack_id, "stack_dir": directory, "stack_dir_visible": True,
+        "path_mismatch": None,
+        "binds": [
+            _bind(os.path.join(directory, "config"), directory),
+            # Too big for a backup: listed, not selected, left out of compose/.
+            _bind(os.path.join(directory, "media"), directory, size=500 * 1024**3,
+                  include=False, reason="larger than 2 GiB"),
+        ],
+        "volumes": [],
+    }
+    monkeypatch.setattr(assets, "inventory", lambda sid, max_bind_bytes=0: json.loads(json.dumps(inv)))
+    return stack_id, directory, inv
+
+
+def _write(directory, rel, content):
+    path = os.path.join(directory, rel)
+    os.makedirs(os.path.dirname(path), exist_ok=True)
+    with open(path, "w") as fh:
+        fh.write(content)
+
+
+def _read(directory, rel):
+    with open(os.path.join(directory, rel)) as fh:
+        return fh.read()
+
+
+def _names(archive):
+    with tarfile.open(archive, "r:gz") as tar:
+        return set(tar.getnames())
+
+
+def run(coro):
+    return asyncio.run(coro)
+
+
+# --------------------------------------------------------------------------- #
+# Backup
+# --------------------------------------------------------------------------- #
+
+
+def test_data_folder_in_stack_dir_stops_the_stack_and_starts_exactly_what_ran(stack, docker):
+    stack_id, directory, _ = stack
+    docker.container("app", "running")
+    docker.container("worker", "exited")  # stopped on purpose
+
+    path, report = run(backup_service.create_backup_ex(stack_id, "S"))
+    try:
+        assert docker.compose_calls == [["stop", "app"], ["start", "app"]]
+        assert report["stopped"] == ["app"]
+        assert report["restart_error"] is None and report["errors"] == []
+        assert [c.state for c in docker.containers] == ["running", "exited"]
+    finally:
+        os.unlink(path)
+
+
+def test_stopped_stack_is_not_started_by_a_backup(stack, docker):
+    stack_id, _, _ = stack
+    docker.container("app", "exited")
+
+    path, _ = run(backup_service.create_backup_ex(stack_id, "S"))
+    os.unlink(path)
+    assert docker.compose_calls == []
+
+
+def test_large_folder_stays_out_but_its_mount_point_stays_in(stack):
+    stack_id, directory, _ = stack
+
+    path, report = run(backup_service.create_backup_ex(stack_id, "S"))
+    try:
+        names = _names(path)
+        manifest = backup_service.read_manifest(path)
+    finally:
+        os.unlink(path)
+    assert {"compose/compose.yaml", "compose/.env", "compose/config/app.db"} <= names
+    assert "compose/media" in names
+    assert not any(n.startswith("compose/media/") for n in names)
+    assert manifest["format_version"] == 3
+    assert manifest["excluded"] == ["media"]
+    assert manifest["compose_binds"] == ["config"]
+    assert [b["source"] for b in report["binds"]] == [os.path.join(directory, "config")]
+
+
+def test_stack_that_cannot_be_stopped_is_not_backed_up(stack, docker):
+    stack_id, _, _ = stack
+    docker.container("app", "running")
+    docker.compose_fail.add("stop")
+
+    with pytest.raises(backup_service.BackupError, match="consistent snapshot"):
+        run(backup_service.create_backup_ex(stack_id, "S"))
+    # Whatever did stop is started again.
+    assert docker.compose_calls[-1] == ["start", "app"]
+
+
+def test_restart_failure_is_reported_not_swallowed(stack, docker):
+    stack_id, _, _ = stack
+    docker.container("app", "running")
+    docker.compose_fail.add("start")
+
+    path, report = run(backup_service.create_backup_ex(stack_id, "S"))
+    os.unlink(path)
+    assert report["restart_error"]
+
+
+def test_failed_volume_is_an_error_and_listed_as_skipped(stack, docker):
+    stack_id, _, inv = stack
+    inv["volumes"].append(_volume(f"{stack_id}_db", stack_id))
+    docker.export_fail.add(f"{stack_id}_db")
+
+    path, report = run(backup_service.create_backup_ex(stack_id, "S"))
+    try:
+        manifest = backup_service.read_manifest(path)
+    finally:
+        os.unlink(path)
+    assert report["errors"] and f"{stack_id}_db" in report["errors"][0]
+    assert manifest["volumes"] == []
+    assert any(s.get("name") == f"{stack_id}_db" and "backup failed" in s["reason"]
+               for s in manifest["skipped"])
+
+
+def test_file_that_shrinks_while_read_keeps_the_archive_valid(tmp_path, monkeypatch):
+    root = tmp_path / "stack"
+    root.mkdir()
+    log = root / "log.txt"
+    log.write_bytes(b"a" * 5000)
+
+    class RotatedMidRead:
+        """The file is truncated after its size was taken, before it is read."""
+
+        def __init__(self, fh):
+            self._fh = fh
+            self.name = fh.name
+
+        def fileno(self):
+            return self._fh.fileno()
+
+        def read(self, n=-1):
+            if log.stat().st_size > 100:
+                os.truncate(log, 100)
+            return self._fh.read(n)
+
+        def __enter__(self):
+            return self
+
+        def __exit__(self, *exc):
+            self._fh.close()
+
+    real_open = open
+
+    def rotating_open(path, mode="r", *args, **kwargs):
+        fh = real_open(path, mode, *args, **kwargs)
+        return RotatedMidRead(fh) if str(path) == str(log) else fh
+
+    monkeypatch.setattr("builtins.open", rotating_open)
+    archive = tmp_path / "a.tar.gz"
+    warnings: list[str] = []
+    with tarfile.open(archive, "w:gz") as tar:
+        backup_service._add_tree(tar, str(root), "compose", set(), warnings)
+    monkeypatch.undo()
+
+    backup_service.verify_archive(str(archive))
+    assert warnings == ["log.txt: changed while it was read"]
+    with tarfile.open(archive, "r:gz") as tar:
+        data = tar.extractfile("compose/log.txt").read()
+    assert data == b"a" * 100 + b"\0" * 4900
+
+
+def test_backup_of_a_busy_stack_is_refused(stack):
+    from sqlmodel import Session
+
+    from database import engine
+    from services import stack_lock_service
+
+    stack_id, _, _ = stack
+    with Session(engine) as session:
+        stack_lock_service.acquire(session, stack_id, "update", "someone")
+        try:
+            with pytest.raises(backup_service.StackBusyError):
+                run(backup_service.create_backup_ex(stack_id, "S"))
+        finally:
+            stack_lock_service.release(session, stack_id)
+
+
+# --------------------------------------------------------------------------- #
+# Restore
+# --------------------------------------------------------------------------- #
+
+
+def _backup(stack_id):
+    path, _ = run(backup_service.create_backup_ex(stack_id, "S"))
+    return path
+
+
+def test_overwrite_restores_the_snapshot_and_keeps_what_was_left_out(stack, docker):
+    stack_id, directory, _ = stack
+    archive = _backup(stack_id)
+    try:
+        # Life goes on after the backup...
+        _write(directory, "config/app.db", "state-after-backup")
+        _write(directory, "config/wal-0002", "newer than the snapshot")
+        _write(directory, "media/movies/new.mkv", "y")
+        _write(directory, "compose.yaml", "services: {}\n")
+
+        result = run(backup_service.restore(archive, overwrite=True))
+    finally:
+        os.unlink(archive)
+
+    assert _read(directory, "config/app.db") == "state-at-backup"
+    assert not os.path.exists(os.path.join(directory, "config/wal-0002"))
+    assert _read(directory, "compose.yaml").startswith("services:\n  app:")
+    assert _read(directory, ".env") == "PASSWORD=hunter2\n"
+    # Not in the backup, so not the restore's to delete.
+    assert _read(directory, "media/movies/big.mkv") == "x" * 100
+    assert _read(directory, "media/movies/new.mkv") == "y"
+    assert result["stack_id"] == stack_id
+    # "media" was left out when the backup was made: listed, but not a problem.
+    assert result["problems"] == []
+    # Nothing staged is left behind or picked up as a stack.
+    root = os.path.dirname(directory)
+    assert not [n for n in os.listdir(root) if n.startswith(".restore-")]
+
+
+def test_restore_stops_a_running_stack_and_brings_it_back_up(stack, docker):
+    stack_id, _, _ = stack
+    archive = _backup(stack_id)
+    docker.container("app", "running")
+    docker.compose_calls.clear()
+    try:
+        result = run(backup_service.restore(archive, overwrite=True))
+    finally:
+        os.unlink(archive)
+    assert docker.compose_calls == [["stop", "app"], ["up", "-d", "--remove-orphans"]]
+    assert result["restarted"] is True
+
+
+def test_without_restore_binds_the_data_folders_are_kept(stack):
+    stack_id, directory, _ = stack
+    archive = _backup(stack_id)
+    try:
+        _write(directory, "config/app.db", "state-after-backup")
+        _write(directory, "compose.yaml", "services: {}\n")
+        run(backup_service.restore(archive, overwrite=True, restore_binds=False))
+    finally:
+        os.unlink(archive)
+    assert _read(directory, "config/app.db") == "state-after-backup"
+    assert _read(directory, "compose.yaml").startswith("services:\n  app:")
+
+
+def test_restore_to_a_new_name_creates_the_stack(stack):
+    stack_id, directory, _ = stack
+    archive = _backup(stack_id)
+    new_id = stack_id + "-copy"
+    try:
+        result = run(backup_service.restore(archive, target_id=new_id))
+    finally:
+        os.unlink(archive)
+    new_dir = compose_service.stack_dir(new_id)
+    assert result["stack_id"] == new_id
+    assert _read(new_dir, "config/app.db") == "state-at-backup"
+    assert os.path.isdir(os.path.join(new_dir, "media"))  # the mount point
+    assert os.listdir(os.path.join(new_dir, "media")) == []
+
+
+def test_existing_stack_without_overwrite_is_refused(stack):
+    stack_id, _, _ = stack
+    archive = _backup(stack_id)
+    try:
+        with pytest.raises(backup_service.BackupError, match="already exists"):
+            run(backup_service.restore(archive))
+    finally:
+        os.unlink(archive)
+
+
+def test_truncated_archive_is_refused_before_anything_is_touched(stack):
+    stack_id, directory, _ = stack
+    archive = _backup(stack_id)
+    with open(archive, "rb") as fh:
+        data = fh.read()
+    with open(archive, "wb") as fh:
+        fh.write(data[: len(data) // 2])
+    _write(directory, "config/app.db", "current")
+    try:
+        with pytest.raises(backup_service.BackupError, match="damaged or incomplete"):
+            run(backup_service.restore(archive, overwrite=True))
+    finally:
+        os.unlink(archive)
+    assert _read(directory, "config/app.db") == "current"
+
+
+def test_archive_cannot_write_through_its_own_symlink(tmp_path):
+    outside = tmp_path / "outside.txt"
+    outside.write_text("untouched")
+    archive = tmp_path / "evil.tar.gz"
+    with tarfile.open(archive, "w:gz") as tar:
+        link = tarfile.TarInfo("compose/x")
+        link.type = tarfile.SYMTYPE
+        link.linkname = str(outside)
+        tar.addfile(link)
+        payload = b"pwned"
+        info = tarfile.TarInfo("compose/x")
+        info.size = len(payload)
+        tar.addfile(info, io.BytesIO(payload))
+    dest = tmp_path / "dest"
+    with tarfile.open(archive, "r:gz") as tar:
+        backup_service._extract_tree(tar, "compose/", str(dest))
+    assert outside.read_text() == "untouched"
+    assert (dest / "x").read_bytes() == b"pwned"
+
+
+def test_volumes_restore_with_their_driver_and_options(stack, docker):
+    stack_id, _, inv = stack
+    vol = _volume(f"{stack_id}_db", stack_id)
+    vol["options"] = {"type": "none", "o": "bind", "device": "/srv/db"}
+    inv["volumes"].append(vol)
+    docker.volumes[f"{stack_id}_db"] = {"files": {"PG_VERSION": b"16"}, "labels": vol["labels"]}
+    archive = _backup(stack_id)
+    del docker.volumes[f"{stack_id}_db"]
+    try:
+        result = run(backup_service.restore(archive, overwrite=True))
+    finally:
+        os.unlink(archive)
+    assert result["volumes_restored"] == 1
+    imported = docker.imported[0]
+    assert imported["driver_opts"] == {"type": "none", "o": "bind", "device": "/srv/db"}
+    assert imported["files"] == {"PG_VERSION": b"16"}
+
+
+def test_renamed_restore_never_touches_the_originals_volumes(stack, docker):
+    stack_id, _, inv = stack
+    inv["volumes"] += [
+        _volume(f"{stack_id}_db", stack_id),
+        # explicit `name:` in compose, so not prefixed with the stack id
+        {**_volume("shared_media", stack_id), "short": "media"},
+    ]
+    docker.volumes[f"{stack_id}_db"] = {"files": {"a": b"1"}, "labels": inv["volumes"][0]["labels"]}
+    docker.volumes["shared_media"] = {"files": {"b": b"2"}, "labels": inv["volumes"][1]["labels"]}
+    archive = _backup(stack_id)
+    new_id = stack_id + "-test"
+    try:
+        result = run(backup_service.restore(archive, target_id=new_id))
+    finally:
+        os.unlink(archive)
+    assert [i["name"] for i in docker.imported] == [f"{new_id}_db"]
+    assert docker.imported[0]["labels"][assets.COMPOSE_PROJECT_LABEL] == new_id
+    reasons = {s.get("name"): s["reason"] for s in result["skipped"] if s["kind"] == "volume"}
+    assert "belongs to stack" in reasons["shared_media"]
+    assert any(p.startswith("shared_media: belongs to stack") for p in result["problems"])
+    assert docker.volumes["shared_media"]["files"] == {"b": b"2"}
+
+
+def test_volume_in_use_by_another_stack_is_not_overwritten(stack, docker):
+    stack_id, _, inv = stack
+    inv["volumes"].append(_volume("common", stack_id, external=True))
+    docker.volumes["common"] = {"files": {"a": b"1"}, "labels": {}}
+    archive = _backup(stack_id)
+    docker.running_users["common"] = ["other-app-1"]
+    try:
+        result = run(backup_service.restore(archive, overwrite=True))
+    finally:
+        os.unlink(archive)
+    assert docker.imported == []
+    assert any("other-app-1" in s["reason"] for s in result["skipped"] if s.get("name") == "common")
+
+
+def test_external_volume_keeps_its_labels(stack, docker):
+    stack_id, _, inv = stack
+    inv["volumes"].append(_volume("common", stack_id, external=True))
+    docker.volumes["common"] = {"files": {"a": b"1"}, "labels": {}}
+    archive = _backup(stack_id)
+    del docker.volumes["common"]
+    try:
+        run(backup_service.restore(archive, overwrite=True))
+    finally:
+        os.unlink(archive)
+    assert docker.imported[0]["labels"] == {}
+
+
+def test_version_2_backup_keeps_its_skipped_folders(stack, tmp_path):
+    """Backups made before this change have no "excluded" list."""
+    stack_id, directory, _ = stack
+    archive = tmp_path / "v2.tar.gz"
+    manifest = {
+        "format_version": 2, "stack_id": stack_id, "name": "S", "stack_dir": directory,
+        "volumes": [], "binds": [],
+        "skipped": [{"kind": "bind", "source": os.path.join(directory, "media"),
+                     "reason": "larger than 2 GiB"}],
+    }
+    with tarfile.open(archive, "w:gz") as tar:
+        data = json.dumps(manifest).encode()
+        info = tarfile.TarInfo("manifest.json")
+        info.size = len(data)
+        tar.addfile(info, io.BytesIO(data))
+        body = b"services: {}\n"
+        info = tarfile.TarInfo("compose/compose.yaml")
+        info.size = len(body)
+        tar.addfile(info, io.BytesIO(body))
+
+    run(backup_service.restore(str(archive), overwrite=True))
+    assert _read(directory, "compose.yaml") == "services: {}\n"
+    assert _read(directory, "media/movies/big.mkv") == "x" * 100
+    assert not os.path.exists(os.path.join(directory, "config"))
+
+
+def test_verify_accepts_a_good_archive_and_rejects_garbage(stack, tmp_path):
+    stack_id, _, _ = stack
+    archive = _backup(stack_id)
+    try:
+        backup_service.verify_archive(archive)
+    finally:
+        os.unlink(archive)
+    junk = tmp_path / "junk.tar.gz"
+    junk.write_bytes(gzip.compress(b"not a tar"))
+    with pytest.raises(backup_service.BackupError):
+        backup_service.verify_archive(str(junk))
+
+
+# --------------------------------------------------------------------------- #
+# Retention and schedules
+# --------------------------------------------------------------------------- #
+
+
+def test_retention_pattern_is_exact():
+    pattern = backup_service.backup_name_pattern("app")
+    assert pattern.match("backup-app-full-20260918-030000.tar.gz")
+    assert pattern.match("backup-app-config-20260918-030000.tar.gz")
+    assert not pattern.match("backup-app-db-full-20260918-030000.tar.gz")
+    assert not pattern.match("backup-app-full-20260918-030000.tar.gz.part")
+
+
+def test_retention_leaves_other_stacks_alone(monkeypatch):
+    from services import schedule_service
+
+    names = [
+        "backup-app-full-20260910-030000.tar.gz",
+        "backup-app-full-20260911-030000.tar.gz",
+        "backup-app-full-20260912-030000.tar.gz",
+        "backup-app-db-full-20260901-030000.tar.gz",
+    ]
+    deleted: list[str] = []
+    monkeypatch.setattr(
+        schedule_service.dest_service, "list_backups",
+        lambda dest: [{"name": n, "modified": i} for i, n in enumerate(names)],
+    )
+    monkeypatch.setattr(schedule_service.dest_service, "delete", lambda dest, n: deleted.append(n))
+
+    assert schedule_service._prune(object(), "app", keep=2) == 1
+    assert deleted == ["backup-app-full-20260910-030000.tar.gz"]
+
+
+def _schedule_env(monkeypatch, db, report=None, error=None):
+    from sqlmodel import Session
+
+    from models.backup_destination import BackupDestination
+    from models.backup_schedule import BackupSchedule
+    from models.stack import Stack
+    from services import schedule_service
+
+    stack_id = f"s{uuid.uuid4().hex[:8]}"
+    alerts: list[str] = []
+    pruned: list[str] = []
+
+    async def fake_create(*args, **kwargs):
+        if error:
+            raise error
+        path = os.path.join(compose_service.stacks_root(), f".{stack_id}.tar.gz")
+        open(path, "wb").close()
+        return path, report
+
+    async def fake_notify(event, title, body, session):
+        alerts.append(title)
+
+    monkeypatch.setattr(schedule_service.backup_service, "create_backup_ex", fake_create)
+    monkeypatch.setattr(schedule_service.dest_service, "upload", lambda d, p, f: f)
+    monkeypatch.setattr(schedule_service, "_prune", lambda d, s, k: pruned.append(s) or 0)
+    monkeypatch.setattr(schedule_service.notify_service, "notify", fake_notify)
+
+    session = Session(db)
+    session.add(Stack(id=stack_id, name=stack_id))
+    dest = BackupDestination(name=f"d-{stack_id}", type="sftp", config="{}")
+    session.add(dest)
+    session.commit()
+    schedule = BackupSchedule(stack_id=stack_id, destination_id=dest.id, frequency="daily")
+    session.add(schedule)
+    session.commit()
+    return schedule_service, session, schedule, alerts, pruned
+
+
+def test_incomplete_scheduled_backup_warns_and_keeps_old_backups(monkeypatch, db):
+    report = {"errors": ["db: helper failed"], "restart_error": None}
+    svc, session, schedule, alerts, pruned = _schedule_env(monkeypatch, db, report=report)
+
+    result = run(svc.run_schedule(session, schedule))
+
+    assert result["ok"] is False
+    assert schedule.last_status.startswith("warning:")
+    assert pruned == []  # the last good backup must not be rotated out
+    assert alerts and "incomplete" in alerts[0]
+
+
+def test_complete_scheduled_backup_is_ok_and_rotates(monkeypatch, db):
+    report = {"errors": [], "restart_error": None}
+    svc, session, schedule, alerts, pruned = _schedule_env(monkeypatch, db, report=report)
+
+    result = run(svc.run_schedule(session, schedule))
+
+    assert result["ok"] is True and schedule.last_status == "ok"
+    assert pruned == [schedule.stack_id] and alerts == []
+
+
+def test_busy_stack_is_retried_soon(monkeypatch, db):
+    error = backup_service.StackBusyError("Stack 'x' is busy: update in progress")
+    svc, session, schedule, alerts, _ = _schedule_env(monkeypatch, db, error=error)
+
+    run(svc.run_schedule(session, schedule))
+
+    assert schedule.last_status.startswith("retrying:")
+    assert (schedule.next_run - schedule.last_run) == svc.BUSY_RETRY
+    assert alerts == []
+
+
+# --------------------------------------------------------------------------- #
+# Routes
+# --------------------------------------------------------------------------- #
+
+
+def test_download_removes_its_temp_file(stack, as_admin, db):
+    from sqlmodel import Session
+
+    from models.stack import Stack
+
+    stack_id, _, _ = stack
+    with Session(db) as session:
+        session.add(Stack(id=stack_id, name=stack_id))
+        session.commit()
+    created: list[str] = []
+    real = backup_service.create_backup_ex
+
+    async def spy(*args, **kwargs):
+        path, report = await real(*args, **kwargs)
+        created.append(path)
+        return path, report
+
+    import routers.backups as routes
+
+    original = routes.backup_service.create_backup_ex
+    routes.backup_service.create_backup_ex = spy
+    try:
+        r = as_admin.get(f"/api/stacks/{stack_id}/backup")
+    finally:
+        routes.backup_service.create_backup_ex = original
+    assert r.status_code == 200
+    header = json.loads(r.headers["X-Stackpilot-Backup"])
+    assert header["errors"] == [] and header["restart_error"] is None
+    assert created and not os.path.exists(created[0])
+
+
+# --------------------------------------------------------------------------- #
+# Inventory
+# --------------------------------------------------------------------------- #
+
+
+class _HelperClient:
+    def __init__(self, output: str):
+        self.output = output
+        self.images = self
+        self.containers = self
+
+    def get(self, image):
+        return object()
+
+    def run(self, image, command, **kwargs):
+        return self.output.encode()
+
+
+def test_inspect_paths_flags_remote_and_unmeasured(monkeypatch):
+    out = "\n".join([
+        "0 dir 1024 ef53",       # local ext4, 1 MiB
+        "1 dir - 6969",          # NFS: not walked
+        "2 dir - ef53",          # du ran out of time
+        "3 file 12 ff534d42",    # a file on CIFS
+    ])
+    monkeypatch.setattr(assets, "get_long_client", lambda: _HelperClient(out))
+    res = assets.inspect_paths(["/a", "/b", "/c", "/d"])
+    assert res["/a"] == {"kind": "dir", "size": 1024 * 1024, "fs": "ef53", "remote": None, "measured": True}
+    assert res["/b"]["remote"] == "nfs" and res["/b"]["measured"] is True
+    assert res["/c"]["measured"] is False
+    assert res["/d"]["remote"] == "cifs"
+
+
+def test_inventory_keeps_remote_and_unmeasured_folders_out(monkeypatch):
+    stack_id = "inv"
+    directory = compose_service.stack_dir(stack_id)
+    specs = [
+        {"source": "/mnt/nas/media", "service": "app", "target": "/media"},
+        {"source": f"{directory}/cache", "service": "app", "target": "/cache"},
+        {"source": f"{directory}/config", "service": "app", "target": "/config"},
+    ]
+    monkeypatch.setattr(assets, "_bind_specs_from_containers", lambda sid: specs)
+    monkeypatch.setattr(assets, "_bind_specs_from_compose", lambda sid: [])
+    monkeypatch.setattr(assets, "compose_volumes", lambda sid: [
+        {**_volume(f"{stack_id}_db", stack_id), "bind_device": "/mnt/nas/db"},
+        _volume("a" * 64, stack_id),
+    ])
+    monkeypatch.setattr(assets, "remote_mount_type", lambda path: None)
+    monkeypatch.setattr(assets, "inspect_paths", lambda paths: {
+        "/mnt/nas/media": {"kind": "dir", "size": None, "fs": "6969", "remote": "nfs", "measured": True},
+        f"{directory}/cache": {"kind": "dir", "size": None, "fs": "ef53", "remote": None, "measured": False},
+        f"{directory}/config": {"kind": "dir", "size": 4096, "fs": "ef53", "remote": None, "measured": True},
+        "/mnt/nas/db": {"kind": "dir", "size": None, "fs": "6969", "remote": "nfs", "measured": True},
+    })
+
+    inv = assets.inventory(stack_id)
+
+    binds = {b["source"]: b for b in inv["binds"]}
+    assert binds["/mnt/nas/media"]["include_default"] is False
+    assert binds["/mnt/nas/media"]["reason"] == "remote storage (nfs)"
+    assert binds[f"{directory}/cache"]["reason"] == "too large to measure"
+    assert binds[f"{directory}/config"]["include_default"] is True
+    vols = {v["name"]: v for v in inv["volumes"]}
+    assert vols[f"{stack_id}_db"]["include_default"] is False
+    assert vols[f"{stack_id}_db"]["reason"] == "remote storage (nfs)"
+    assert "anonymous" in vols["a" * 64]["reason"]
+
+
+def test_external_volumes_are_found(monkeypatch):
+    stack_id = f"s{uuid.uuid4().hex[:8]}"
+    directory = compose_service.stack_dir(stack_id)
+    os.makedirs(directory)
+    _write(directory, "compose.yaml",
+           "services:\n  app:\n    image: img\n    volumes: [shared:/data]\n"
+           "volumes:\n  shared:\n    external: true\n    name: ${SHARED:-common}\n")
+
+    class Vol:
+        def __init__(self, name, attrs):
+            self.name, self.attrs = name, attrs
+
+    class Client:
+        def __init__(self):
+            self.volumes = self
+            self.containers = self
+
+        def list(self, **kwargs):
+            if "all" in kwargs:  # containers
+                return []
+            return [Vol(f"{stack_id}_db", {"Labels": {assets.COMPOSE_PROJECT_LABEL: stack_id}})]
+
+        def get(self, name):
+            if name != "common":
+                raise assets.DockerError("not_found")
+            return Vol("common", {"Labels": {}, "Driver": "local"})
+
+    client = Client()
+    monkeypatch.setattr(assets, "get_client", lambda: client)
+
+    vols = {v["name"]: v for v in assets.compose_volumes(stack_id)}
+    assert set(vols) == {f"{stack_id}_db", "common"}
+    assert vols["common"]["external"] is True
+    assert vols[f"{stack_id}_db"]["external"] is False

backend/version.py

@@ -1,3 +1,3 @@
 """Single source of truth for the StackPilot release version."""
 
-APP_VERSION = "0.63.0"
+APP_VERSION = "0.64.0"

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "stackpilot-frontend",
   "private": true,
-  "version": "0.63.0",
+  "version": "0.64.0",
   "type": "module",
   "scripts": {
     "dev": "vite",

frontend/src/api/backups.ts

@@ -18,6 +18,8 @@ export interface BackupBind {
   covered_by_compose: boolean;
   via: "compose" | "archive";
   system: boolean;
+  /** Network filesystem the folder sits on (nfs, cifs, …); never archived. */
+  remote?: string | null;
   include_default: boolean;
   selected: boolean;
   reason: string | null;
@@ -29,6 +31,8 @@ export interface BackupVolume {
   driver: string;
   remote: boolean;
   remote_type: string | null;
+  /** Used by the stack but not created by compose for it (external: true). */
+  external?: boolean;
   include_default: boolean;
   selected: boolean;
   reason: string | null;
@@ -49,6 +53,14 @@ export interface BackupReport {
   volumes: { name: string; bytes: number | null; error: string | null }[];
   skipped: { kind: string; source?: string; name?: string; reason: string | null }[];
   path_mismatch: { host: string; container: string } | null;
+  /** Services stopped for a consistent snapshot (and started again). */
+  stopped?: string[];
+  /** Data that should have been captured and was not. */
+  errors?: string[];
+  /** Files that changed or could not be read while archiving. */
+  warnings?: string[];
+  /** Set when the stack could not be started again after the backup. */
+  restart_error?: string | null;
 }
 
 export interface RestoreResult {
@@ -57,6 +69,9 @@ export interface RestoreResult {
   volumes_restored: number;
   binds_restored?: number;
   skipped?: { kind: string; source?: string; name?: string; reason: string | null }[];
+  /** What went wrong during this restore (not what the backup left out). */
+  problems?: string[];
+  restarted?: boolean;
 }
 
 export interface BackupOptions {

frontend/src/components/stacks/BackupRestore.tsx

@@ -150,6 +150,25 @@ export function BackupButton({ stackId }: { stackId: string }) {
     const skipped = report.skipped.filter((s) => s.reason !== "not requested").length;
     return `Backup: ${parts.join(" · ")}${skipped ? ` — ${skipped} skipped` : ""}`;
   };
+  // A backup that is missing data, or left the stack down, is not a success.
+  const announce = (tid: string | number, text: string, report?: BackupReport | null) => {
+    const problems = [
+      ...(report?.errors ?? []).map((e) => `Not captured: ${e}`),
+      ...(report?.restart_error ? [`Stack did not start again: ${report.restart_error}`] : []),
+    ];
+    if (problems.length) {
+      toast.error(`${text} — incomplete`, { id: tid, description: problems.join("\n") });
+    } else if (report?.warnings?.length) {
+      toast.warning(text, {
+        id: tid,
+        description: `${report.warnings.length} file(s) changed while being read: ${report.warnings
+          .slice(0, 3)
+          .join("; ")}`,
+      });
+    } else {
+      toast.success(text, { id: tid });
+    }
+  };
 
   const run = async () => {
     setBusy(true);
@@ -166,7 +185,7 @@ export function BackupButton({ stackId }: { stackId: string }) {
       };
       if (target === "download") {
         const report = await backupsApi.download(stackId, opts);
-        toast.success(describe(report), { id: tid });
+        announce(tid, describe(report), report);
       } else {
         const body = {
           destination_id: Number(target),
@@ -177,7 +196,7 @@ export function BackupButton({ stackId }: { stackId: string }) {
           volumes: opts.volumes,
         };
         const res = await backupsApi.push(stackId, body);
-        toast.success(`Pushed to ${res.destination}`, { id: tid });
+        announce(tid, `Pushed to ${res.destination} — ${describe(res.report)}`, res.report);
       }
       setOpen(false);
     } catch (e) {
@@ -246,6 +265,7 @@ export function BackupButton({ stackId }: { stackId: string }) {
                     detail={`named volume (${v.driver})`}
                     badges={[
                       ...(v.remote ? [{ text: v.remote_type || "remote", tone: "warn" as const }] : []),
+                      ...(v.external ? [{ text: "external" }] : []),
                       ...(v.reason && !v.remote ? [{ text: v.reason, tone: "warn" as const }] : []),
                     ]}
                   />
@@ -257,8 +277,9 @@ export function BackupButton({ stackId }: { stackId: string }) {
                 )}
               </div>
               <p className="mt-1 text-[11px] text-slate-500">
-                Remote storage (NFS/CIFS) is unchecked by default — it lives on your NAS and would be
+                Remote storage (NFS/CIFS volumes, and folders on a mounted share) is never selected by
-                overwritten on restore.
+                default — it lives on your NAS. The stack is stopped while its data is read and
+                started again afterwards.
               </p>
             </div>
 
@@ -354,7 +375,12 @@ export function RestoreButton() {
       }
       const bits = [`${res.volumes_restored} volume(s)`];
       if (res.binds_restored) bits.push(`${res.binds_restored} folder(s)`);
-      toast.success(`Restored '${res.stack_id}' — ${bits.join(", ")}`, { id: tid });
+      const text = `Restored '${res.stack_id}' — ${bits.join(", ")}`;
+      if (res.problems?.length) {
+        toast.warning(text, { id: tid, description: res.problems.slice(0, 5).join("\n") });
+      } else {
+        toast.success(text, { id: tid });
+      }
       qc.invalidateQueries({ queryKey: ["stacks"] });
       setOpen(false);
       setFile(null);
@@ -464,7 +490,7 @@ export function RestoreButton() {
               checked={overwrite}
               onChange={setOverwrite}
               label="Overwrite if a stack with this id already exists"
-              hint="Replaces the existing stack files and volume contents."
+              hint="Stops the stack, puts back the files, folders and volumes in the backup and starts it again. Folders the backup left out are kept."
             />
           </div>
           <div className="mt-4 flex justify-end gap-2">