Ceph RGW updates quota statistics asynchronously, which means user stats may lag behind the actual current usage. To get the latest quota usage numbers, run user stats with --sync-stats before reading them. This guide covers how to view quota settings and update stats effectively.

Why Stats Need to Be Synced

Quota stats are updated asynchronously. The documented way to refresh the latest user quota usage is to run radosgw-admin user stats --uid <uid> --sync-stats before reading user stats output. Ceph also caches quota statistics on each RGW instance, so quota enforcement across multiple gateways is not perfectly synchronized unless those cache and sync intervals are tuned.

Viewing User Quota and Current Stats

Always sync before viewing to get accurate numbers:

# Sync and view current user usage
radosgw-admin user stats --uid alice --sync-stats

# View configured quota settings
radosgw-admin user info --uid alice

Look for the stats section in user stats output:

{
  "stats": {
    "size": 5368709120,
    "size_actual": 5368709120,
    "num_objects": 45000
  }
}

Look for the user_quota section in user info output:

{
  "user_id": "alice",
  "user_quota": {
    "enabled": true,
    "max_size_kb": 10485760,
    "max_objects": 1000000
  }
}

Viewing Bucket Quota and Stats

# View bucket stats
radosgw-admin bucket stats --bucket mybucket

# View the bucket quota configured for buckets owned by alice
radosgw-admin user info --uid alice | jq '.bucket_quota'

Unlike user stats, the documented --sync-stats flag does not apply to bucket stats. The bucket sync enable and bucket sync disable commands are multisite sync controls, not usage refresh commands.

Getting Quota Settings Only

# User quota settings
radosgw-admin user info --uid alice | jq '.user_quota'

# Bucket quota settings for buckets owned by the user
radosgw-admin user info --uid alice | jq '.bucket_quota'

Syncing Stats for All Buckets of a User

# Refresh the user's quota stats from the current bucket indexes
radosgw-admin user stats --uid alice --sync-stats

Global Stats Sync

To refresh quota stats for all users:

radosgw-admin user list | jq -r '.[]' | while read -r USER_ID; do
  radosgw-admin user stats --uid "$USER_ID" --sync-stats
done

Monitoring Quota Usage Percentage

A script to check quota utilization:

#!/bin/bash
USER_ID=$1
STATS=$(radosgw-admin user stats --uid "$USER_ID" --sync-stats)
USED=$(echo "$STATS" | jq -r '.stats.size // 0')
MAX_KB=$(radosgw-admin user info --uid "$USER_ID" | jq -r '.user_quota.max_size_kb // -1')

if [ "$MAX_KB" != "-1" ] && [ "$MAX_KB" -gt 0 ]; then
  MAX=$((MAX_KB * 1024))
  PERCENT=$(echo "scale=1; $USED * 100 / $MAX" | bc)
  echo "User $USER_ID: ${PERCENT}% of quota used ($USED / $MAX bytes)"
else
  echo "User $USER_ID: no quota limit set"
fi

Summary

Accurate quota and usage reporting in Ceph RGW requires syncing user stats with --sync-stats before reading them, since RGW updates quota stats asynchronously. Use user info for the configured limits and user stats or bucket stats for current consumption. Build periodic stat-sync jobs to keep user quota reporting current and reduce stale usage data.