backup: exclude /anca-elements/ from nfs-mirror + offsite Step 1

Anca's photos are being ingested into Immich (started 2026-05-24
afternoon), so /srv/nfs/immich/library/ becomes the canonical copy
for those photos. The separate /srv/nfs/anca-elements/ archive tree
+ its sda mirror at /mnt/backup/anca-elements/ are now redundant.

Going forward:
- nfs-mirror EXCLUDES /anca-elements/ so future weekly runs don't
  re-touch the 771G subtree (also no longer required since Immich
  has the data via its NFS library).
- offsite-sync Step 1 also excludes /anca-elements/ — the historical
  771G under /mnt/backup/anca-elements/ stays on sda for now but is
  NOT shipped to Synology pve-backup/ (Immich's library reaches
  Synology via Step 2 bypass leg anyway).

The 771G on /mnt/backup/anca-elements/ will be cleaned up manually
once Immich ingest completes and we verify all photos are in the
Immich library. Same for /srv/nfs/anca-elements/ on sdc thin pool —
freeing both would reclaim ~1.5 TB across sdc + sda.

In-flight context: today's nfs-mirror first run was killed mid-flight
at ~70% (was at /srv/nfs/postgresql/). The killed run wrote ~200G of
service NFS subtrees to /mnt/backup/<svc>/, then sda hit 95% used,
prompting this change. Next nfs-mirror run will not touch
anca-elements and will fit comfortably (~250G total for the keep-list
minus anca-elements).

scripts/nfs-mirror.sh

@@ -57,6 +57,14 @@ EXCLUDES=(
     --exclude='/.lv-pvc-mapping.json'
     --exclude='/.nfs-changes.log'
 
+    # ---- anca-elements: photos are being ingested into Immich (2026-05-24),
+    # so /srv/nfs/immich/library/ becomes the canonical copy and the separate
+    # anca-elements tree is redundant. Excluded from nfs-mirror going forward.
+    # The historical 771G at /mnt/backup/anca-elements/ stays put until manual
+    # cleanup once Immich ingest completes; offsite-sync Step 1 also excludes
+    # it from the Synology pve-backup/ upload so we don't ship the redundant copy.
+    --exclude='/anca-elements/'
+
     # ---- NFS paths: too big / transient / re-fetchable ----
     --exclude='/immich/'
     --exclude='/frigate/'

scripts/offsite-sync-backup.sh

@@ -70,12 +70,16 @@ if [ "${DAY_OF_MONTH}" -le 7 ] || [ -n "${FORCE_FULL}" ]; then
         --exclude='.lv-pvc-mapping.json' \
         --exclude='.nfs-changes.log' \
         --exclude='.force-full-sync' \
+        --exclude='/anca-elements/' \
         "${BACKUP_ROOT}/" "${PVE_BACKUP_DEST}/" 2>&1 || STATUS=1
     rm -f "${FORCE_FULL_FLAG}"
 elif [ -s "${MANIFEST}" ]; then
     MANIFEST_LINES=$(wc -l < "${MANIFEST}")
     log "Incremental sync (${MANIFEST_LINES} files from manifest)..."
+    # /anca-elements is being ingested into Immich (Immich becomes canonical) —
+    # skip the redundant copy in /mnt/backup/anca-elements/ until manual cleanup.
     rsync -rlt --chmod=Du=rwx,Dgo=rx,Fu=rw,Fog=r --files-from="${MANIFEST}" \
+        --exclude='anca-elements/' \
         "${BACKUP_ROOT}/" "${PVE_BACKUP_DEST}/" 2>&1 || STATUS=1
 else
     log "No changed files in manifest, nothing to sync"