# Backup and restore

What protects production's data, what each part does and does not cover, and how to get it back. See #147.

## What runs

Two services in `docker-compose.prod.yml`, alongside the app and the database.

| Service | What | When | Kept | Lands in |
| --- | --- | --- | --- | --- |
| `redefined-designs-db-backup-syn` | `pg_dump` of `redefined`, gzipped | Daily, 03:00 | 7 daily, 4 weekly, 6 monthly | `/volume1/configs/redefined-designs/backups/postgres` |
| `redefined-designs-uploads-backup-syn` | `tar.gz` of the uploads directory | Weekly, Sunday 04:00 | 56 days | `/volume1/configs/redefined-designs/backups/uploads` |

Both destinations are bind mounts that have to exist before the stack starts. Nothing creates them, and nothing complains when they are missing — the container sits in **Created**, never runs, and so has no logs to explain itself. Creating them is a step in the cutover runbook; on any other deploy, check for them first:

```bash
sudo mkdir -p /volume1/configs/redefined-designs/backups/{postgres,uploads}
sudo docker ps --filter name=backup --format '{{.Names}}	{{.Status}}'
```

Both prune automatically. Both report **unhealthy** when their newest artifact is older than their interval plus grace, so a regime that has quietly stopped shows up in Portainer's stack view beside the app rather than being discovered during a restore.

The database dumper is pinned to `prodrigestivill/postgres-backup-local:16`, matching the server's major version. `pg_dump` refuses to dump a server newer than itself, so a floating tag would be a backup that stops working the day Postgres is upgraded — silently, because nothing reads the dumps until they are needed.

## What this does not protect against

Three gaps, stated plainly because a backup you are wrong about is worse than one you know the limits of.

**The disk.** Both artifact directories are on `/volume1`, the same volume as the live database and uploads. This protects against a bad migration, a dropped table, a bad deploy and a stack deletion. It does not protect against the volume failing. **Getting a copy off `/volume1` is a Synology-side job** — Hyper Backup to another volume, an external disk, or offsite — and until that exists this is a convenience rather than a guarantee.

**The stack's own teardown.** These services run while the stack runs. Deleting the Portainer stack deletes them along with everything else, so they cannot cover the moment they would be most wanted. The manual `pg_dump` in README's deploy steps stays for exactly that reason: a routine regime and a snapshot before a risky operation are different jobs, and neither replaces the other.

**The gap between the two.** The database is dumped daily and uploads weekly, so a restore pairs a database from one moment with images from another. Two mismatches are possible. An image with no row is harmless — an orphaned file nobody references. A row with no image is a broken thumbnail on one recent item, and the original is usually recoverable, because an admin who added an item that recently still has the photograph. Neither is data loss, and paying for a synchronised snapshot to avoid a recoverable broken thumbnail is not worth the complexity.

## Checking it is working

```bash
# Both should say (healthy). unhealthy means nothing has been written inside
# the window — the regime has stopped, and this is the whole point of the check.
sudo docker ps --filter "name=backup" --format "{{.Names}}\t{{.Status}}"

# What is actually on disk, newest last.
ls -lht /volume1/configs/redefined-designs/backups/postgres/daily | head
ls -lht /volume1/configs/redefined-designs/backups/uploads | head
```

A dump whose size is wildly different from its predecessors is worth opening. A dump that is a few hundred bytes is a failed dump that exited successfully.

## Restoring the database

**Read this before running it.** `--clean --if-exists` is baked into the dumps, so restoring **drops and recreates every table it touches**. Against production that discards whatever is currently there. Take a fresh dump first, whatever state you think the database is in.

### 1. Practise on a throwaway database first

This is not optional ceremony. An untested backup is a file of unknown validity, and the failure modes — a truncated dump, a dump taken mid-migration — look exactly like a good one until the day it matters.

```bash
BACKUP=/volume1/configs/redefined-designs/backups/postgres/daily/redefined-<date>.sql.gz

sudo docker exec -i redefined-designs-db-syn \
  psql -U redefined -d postgres -c "CREATE DATABASE restore_test"

gunzip -c "$BACKUP" | sudo docker exec -i redefined-designs-db-syn \
  psql -U redefined -d restore_test
```

Then verify it is a real database rather than an empty one:

```bash
# Row counts against the tables that matter. Compare them with production.
sudo docker exec -i redefined-designs-db-syn psql -U redefined -d restore_test -c "
  SELECT 'items' AS t, count(*) FROM items
  UNION ALL SELECT 'customers', count(*) FROM customers
  UNION ALL SELECT 'orders',    count(*) FROM orders
  UNION ALL SELECT 'checkouts', count(*) FROM checkouts;"

# And that the schema is at the same migration as the code expects.
sudo docker exec -i redefined-designs-db-syn psql -U redefined -d restore_test \
  -c "SELECT name FROM pgmigrations ORDER BY id DESC LIMIT 1"

sudo docker exec -i redefined-designs-db-syn \
  psql -U redefined -d postgres -c "DROP DATABASE restore_test"
```

The migration check is the one most easily skipped and the most likely to bite: a dump older than the current code restores a schema the app will fail against on boot. The container runs `migrate.js up` at start, so it may repair itself — but only forwards, and only if the migrations are still compatible.

### 2. Restore for real

```bash
# Stop the app so nothing writes while the schema is being replaced.
sudo docker stop redefined-designs-syn

gunzip -c "$BACKUP" | sudo docker exec -i redefined-designs-db-syn \
  psql -U redefined -d redefined

sudo docker start redefined-designs-syn

# Migrations run at container start, so watch them land before serving.
sudo docker logs -f redefined-designs-syn | head -30
```

## Restoring uploads

The archives are plain `tar.gz` unless `BACKUP_PASSPHRASE` is set in the stack.

```bash
ARCHIVE=/volume1/configs/redefined-designs/backups/uploads/uploads-<date>.tar.gz

# Look before extracting. The archive contains a `backup/uploads/` prefix.
tar -tzf "$ARCHIVE" | head

# Extract somewhere harmless first, then move what is needed into place.
mkdir -p /volume1/configs/redefined-designs/restore-tmp
tar -xzf "$ARCHIVE" -C /volume1/configs/redefined-designs/restore-tmp
```

Restore into the live directory by copying rather than replacing it wholesale, unless the intent really is to discard everything added since the archive was taken. Image paths are stored in the database as `/uploads/<file>`, so a file missing from disk is a broken image on one item rather than an error, which makes a partial restore safe and a wrong wholesale one quietly destructive.

### On `BACKUP_PASSPHRASE`

Leave it unset unless there is a reason. If it is set, the archives are GPG-encrypted, and **an archive nobody can decrypt is not a backup**. A passphrase kept only in Portainer's stack variables is lost with the NAS — precisely the disaster the backups exist for. Set it only if the passphrase itself lives somewhere that survives the NAS.

## Open

- [ ] An off-`/volume1` copy, by whatever Synology-side mechanism is chosen, recorded here once it exists
- [ ] A restore performed at least once against `restore_test` and the result verified, per the section above

Neither is done. Until the second one is, this document describes an untested procedure.