# ana-nas → nh3-nas restic mirror

Nightly rsync of the Ana-side restic repo to the NH3 Synology, giving
file-level backups cross-site redundancy independent of the PBS layer.

## What + where

| | |
|---|---|
| **Source** | `ana-nas:/mnt/backup/restic/repo/ana/` (ZFS `NASPool/backupStore`, written by rest-server-ana on ana-docker via NFS). |
| **Target** | `nh3-nas:/volume1/Backup/restic-ana-mirror/` (Btrfs `/volume1`, 16 TB free at setup time). |
| **Runs on** | `ana-nas` (Debian 12, VMID 100 on pfi-pve). |
| **Runs as** | `lkraven` (uid 1000) — owns the source data natively; no sudo needed. |
| **Auth** | Dedicated ed25519 keypair `~lkraven/.ssh/id_mirror_nh3` → `syncuser@nh3-nas`. No passphrase (for unattended systemd runs). |
| **Schedule** | Daily at 04:00, `Persistent=true`, 300s randomized delay. |

## Scheduling rationale

Window sits between:
- **01:00–03:00** — ana-side restic clients run their nightly backups
  against rest-server-ana. We wait until those are clearly done before
  reading the repo.
- **06:00** — PBS-ANA → PBS-NH3 sync job pulls fresh snapshots across
  the WAN. Running the restic mirror earlier avoids competing for WAN
  bandwidth with the (much larger) PBS sync.

## Files

| File | Install path on ana-nas |
|---|---|
| `restic-mirror-to-nh3.service` | `/etc/systemd/system/restic-mirror-to-nh3.service` |
| `restic-mirror-to-nh3.timer`   | `/etc/systemd/system/restic-mirror-to-nh3.timer` |

These are the canonical copies; the on-host copies mirror them.

## Deploy / redeploy

```bash
cd configs/rsync/ana-nas-to-nh3
scp restic-mirror-to-nh3.{service,timer} ana-nas:/tmp/
ssh -t ana-nas 'sudo install -m 644 /tmp/restic-mirror-to-nh3.service /etc/systemd/system/ && \
                sudo install -m 644 /tmp/restic-mirror-to-nh3.timer   /etc/systemd/system/ && \
                sudo systemctl daemon-reload && \
                sudo systemctl enable --now restic-mirror-to-nh3.timer && \
                sudo systemctl list-timers restic-mirror-to-nh3.timer'
```

## Operate

```bash
# Trigger a run manually (e.g. to smoke-test changes)
ssh -t ana-nas 'sudo systemctl start restic-mirror-to-nh3.service'

# Follow a running transfer
ssh ana-nas 'journalctl -u restic-mirror-to-nh3.service -f'

# Last run outcome
ssh ana-nas 'systemctl status restic-mirror-to-nh3.service --no-pager'

# When the timer fires next
ssh ana-nas 'systemctl list-timers restic-mirror-to-nh3.timer'
```

## Restore flow (if ana-nas loses the repo)

The mirror is just files — point a restic client directly at the
nh3-nas copy. Options:

**Option A — pull repo back to ana-nas and use rest-server-ana as
before.** rsync in reverse:

```bash
ssh -t ana-nas 'sudo rsync -a \
  -e "ssh -i /home/lkraven/.ssh/id_mirror_nh3" \
  syncuser@10.100.50.50:/volume1/Backup/restic-ana-mirror/ \
  /mnt/backup/restic/repo/ana/'
```

**Option B — restic against the mirror directly.** Expose
`/volume1/Backup/restic-ana-mirror/` via a temporary rest-server or
NFS share, point the client at it for an emergency restore. Slow (WAN
hop) but no dataset copy required.

Target is `--append-only: false` on the mirror side — not a problem
for restore, but means a compromised mirror side *could* be tampered
with. Balanced against the operational cost of managing an
append-only mirror, we accept this for a mirror-of-a-mirror.

## What this does NOT cover

- **PBS snapshots** — those replicate via PBS-ANA → PBS-NH3 (a
  separate pipeline; see `docs/runbooks/pbs-deployment.md`).
- **rest-server-nh3's own data** — nh3-docker + nh3-dev backups that
  land on `/volume1/Backup/restic/<user>/`. Those are already at the
  NH3 Synology; ANA-side doesn't mirror them currently. Symmetric
  mirror back to ana-nas is a future-work item.
