Administration

Common operations:

• Initialize Instance
• Reconfigure
• Remove Instance
• Add New Instance
• Shared Mount Across Nodes
• PITR Recovery
• Troubleshooting
• Performance Tuning

See FAQ for more.

Initialize Instance

./juice.yml -l <host>
./juice.yml -l <host> -e fsname=<name>

Initialization steps:

• Install juicefs package
• Create shared cache dir (default /data/juice)
• Run juicefs format --no-update (only effective on first creation)
• Create mount point and set permissions
• Render systemd unit and env files
• Start service and wait for metrics port
• Register to VictoriaMetrics (if infra node exists)

Reconfigure

After changing config, it’s recommended to run (update config and ensure service is online):

./juice.yml -l <host> -t juice_config,juice_launch

Render config without touching service state:

./juice.yml -l <host> -t juice_config

Notes:

• juice_config,juice_launch ensures service is started, but does not force-restart an already running instance
• data only takes effect on the first format
• After changing mount options, manually restart the instance service (systemctl restart juicefs-<name>)

Remove Instance

1. Set instance state to absent
2. Run juice_clean

juice_instances:
  jfs:
    path: /fs
    meta: postgres://...
    state: absent

./juice.yml -l <host> -t juice_clean,juice_register
./juice.yml -l <host> -e fsname=jfs -t juice_clean,juice_register

Removal actions:

• Stop systemd service
• umount -l lazy unmount
• Remove unit and env files
• Reload systemd
• Rewrite this node’s VictoriaMetrics target file, removing instances with state=absent

PostgreSQL metadata, PostgreSQL jfs_blob data tables, and object-storage data are not deleted.

Running only -t juice_clean does not update monitoring targets and temporarily leaves stale scrape endpoints for removed instances. The commands above therefore run juice_register as well.

Add New Instance

Add a new instance in config, ensure unique port:

juice_instances:
  newfs:
    path: /newfs
    meta: postgres://...
    data: --storage minio --bucket https://sss.pigsty:9000/newfs --access-key <s3_access_key> --secret-key <s3_secret_key>
    port: 9568

Deploy:

./juice.yml -l <host> -e fsname=newfs

Shared Mount Across Nodes

Configure the same meta and instance name on multiple nodes:

app:
  hosts:
    10.10.10.11: { juice_instances: { shared: { path: /shared, meta: "postgres://...", port: 9567 } } }
    10.10.10.12: { juice_instances: { shared: { path: /shared, meta: "postgres://...", port: 9567 } } }

Only one node needs to format the filesystem; others will skip via --no-update.

PITR Recovery

JuiceFS metadata and data must be restored to a mutually consistent state. Before any restore, stop every writer and unmount/stop the corresponding JuiceFS service on every client, identify the exact PostgreSQL cluster and target time, and confirm an available backup:

# Inspect Patroni members; inspect the target stanza's backup on a database node
pig pt list <cluster>
pig pb info -s <stanza>

# On the target database node, run the restore command as postgres
sudo -iu postgres pg-pitr -s <stanza> -t "2026-08-14 10:30:00+08"

If metadata and the --storage postgres jfs_blob table are in the same restored PostgreSQL database, database PITR can return both to one point in time. If they reside in different databases or clusters, design a coordinated recovery point for both.

If file data is in Silo/S3, PostgreSQL PITR rolls back metadata only, not objects. Newer objects may remain, while old objects that were deleted or collected may be unavailable. Recoverability depends on object versioning, trash, and lifecycle policies; do not run garbage collection until validation is complete.

Troubleshooting

Mount Fails

systemctl status juicefs-jfs
journalctl -u juicefs-jfs -f
mountpoint /fs

Metadata Connection Issues

psql "postgres://dbuser_meta:[email protected]:5432/meta" -c "SELECT 1"

Metrics Port Check

ss -tlnp | grep 9567
curl http://localhost:9567/metrics

Performance Tuning

Pass juicefs mount options via mount:

juice_instances:
  jfs:
    path: /fs
    meta: postgres://...
    mount: --cache-size 102400 --prefetch 3 --max-uploads 50

Key metrics to watch:

• juicefs_blockcache_hits/juicefs_blockcache_miss: cache hit ratio
• juicefs_object_request_durations_histogram_seconds: object storage latency
• juicefs_transaction_durations_histogram_seconds: metadata transaction latency