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OM metadata backup (including bucket snapshots)

Back up Ozone Manager (OM) namespace metadata, including bucket snapshot RocksDB state, with ozone repair om download (HDDS-16171). This is not a substitute for Datanode block or SCM metadata backups.

The command uses the same v2 checkpoint transfer as OM follower bootstrap (design doc). It handles multi-batch download and hard link reconstruction, and writes a ready-to-install tree under --output-dir.

Requires Ozone 2.2+ with HDDS-16171.

What is included​

  • om.db — volumes, buckets, keys, and related AOS metadata
  • db.snapshots — bucket snapshot RocksDB state (when snapshots exist on the leader)
  • Compaction backup and log directories needed to read snapshot SST files

Backup​

Requirements: ozone-site.xml on the host; kinit in secure clusters (ozone.administrators).

ozone repair om download --output-dir /backup/om-metadata --overwrite

# OM HA — add --service-id; --node-id targets a specific OM (leader recommended)
ozone repair om download \
  --service-id <om-service-id> \
  --node-id <om-node-id> \
  --output-dir /backup/om-metadata \
  --overwrite

tar -czf om-metadata-$(date +%Y%m%d).tar.gz -C /backup om-metadata

Store archives off-cluster according to your retention policy.

Restore​

Stop the target OM before installing metadata. If a live OM is still up, re-run ozone repair om download. Otherwise extract a saved archive:

mkdir -p /restore
tar -xzf om-metadata-YYYYMMDD.tar.gz -C /restore

OM_DB_DIRS=/var/lib/ozone/om/metadata
rm -rf "$OM_DB_DIRS/om.db" "$OM_DB_DIRS/db.snapshots"
rsync -a /restore/om-metadata/ "$OM_DB_DIRS/"

# Start OM; verify with: ozone sh volume list

For HA with an intact Ratis ring, prefer ozone om --bootstrap over manual install. See Replacing Ozone Manager disks and Ozone Repair.

Operational notes​

  • When using --node-id, target the leader OM.
  • Schedule backups during low snapshot activity; including snapshot data takes a short-lived cache lock.
  • Do not use Recon as a backup source (includeSnapshotData=false by design).
  • User-visible Ozone Snapshots are included. Ratis snapshots (OM HA replication) are a separate concept — see OM high availability.
PropertyDefaultRelevance
ozone.om.db.checkpoint.use.inode.based.transfertrueRequired for snapshot-inclusive backup
ozone.administrators(none)CLI access in secure mode

See also​