offsite-sync-backup + nfs-change-tracker: exclude /srv/nfs/anca-elements

The 771G under /srv/nfs/anca-elements is a downstream replica synced
FROM Synology (/volume1/Backup/Anca/Elements) by anca-elements-sync.sh.
The offsite-sync pipeline was copying it back to Synology under
/volume1/Backup/Viki/nfs/anca-elements, creating a self-duplicate
(~122G already partially copied during the last monthly full sync).

- nfs-change-tracker.service: drop anca-elements/ from inotify watch
  (incremental syncs no longer queue these paths)
- offsite-sync-backup.sh: --exclude='anca-elements/' on the monthly
  full rsync; grep -v on the incremental files-from list

Deployed to 192.168.1.127:/usr/local/bin/offsite-sync-backup +
/etc/systemd/system/nfs-change-tracker.service; service reloaded.

scripts/nfs-change-tracker.service

@@ -7,7 +7,7 @@ Type=simple
 ExecStart=/usr/bin/inotifywait -m -r \
     --format '%%w%%f' \
     -e create -e modify -e moved_to -e delete \
-    --exclude '(/\..*swp$|/\.nfs|/\.Trash|\.db-shm$|\.db-wal$|\.db-journal$|/stats/.*\.stat$)' \
+    --exclude '(/\..*swp$|/\.nfs|/\.Trash|\.db-shm$|\.db-wal$|\.db-journal$|/stats/.*\.stat$|^/srv/nfs/anca-elements/)' \
     /srv/nfs \
     /srv/nfs-ssd
 StandardOutput=append:/mnt/backup/.nfs-changes.log

scripts/offsite-sync-backup.sh

@@ -78,8 +78,10 @@ log "--- Step 2: NFS → Synology (change-tracked) ---"
 
 if [ "${DAY_OF_MONTH}" -le 7 ]; then
     # Monthly: full sync with --delete for cleanup
+    # anca-elements/ is excluded — source of truth is Synology /volume1/Backup/Anca/Elements;
+    # the PVE copy is a downstream replica, syncing it back would just duplicate ~770G.
     log "Monthly full NFS sync..."
-    rsync -rltz --delete /srv/nfs/ "${NFS_DEST}/" 2>&1 \
+    rsync -rltz --delete --exclude='anca-elements/' /srv/nfs/ "${NFS_DEST}/" 2>&1 \
         && log "  OK: nfs/ full sync" || { warn "nfs/ full sync failed"; STATUS=1; }
     rsync -rltz --delete /srv/nfs-ssd/ "${NFS_SSD_DEST}/" 2>&1 \
         && log "  OK: nfs-ssd/ full sync" || { warn "nfs-ssd/ full sync failed"; STATUS=1; }
@@ -88,8 +90,9 @@ elif [ -s "${NFS_CHANGE_LOG}" ]; then
     # Incremental: only sync files logged by inotifywait
     sort -u "${NFS_CHANGE_LOG}" > /tmp/nfs-changes-deduped
 
-    # HDD NFS
+    # HDD NFS — drop anca-elements/* paths (excluded from offsite; see Monthly block)
     grep '^/srv/nfs/' /tmp/nfs-changes-deduped | \
+        grep -v '^/srv/nfs/anca-elements/' | \
         while IFS= read -r f; do [ -f "$f" ] && echo "${f#/srv/nfs/}"; done \
         > /tmp/sync-nfs.list 2>/dev/null
     NFS_COUNT=$(wc -l < /tmp/sync-nfs.list 2>/dev/null || echo 0)