Synchronizing data in a multi-site Ceph Object Gateway configuration

Edit online

In a multi-site Ceph Object Gateway configuration of a storage cluster, failover and failback causes data synchronization to stop. The radosgw-admin sync status command reports that the data sync is behind for an extended period of time.

About this task

You can run the radosgw-admin data sync init command to synchronize data between the sites and then restart the Ceph Object Gateway. This command does not touch any actual object data and initiates data sync for a specified source zone. It causes the zone to restart a full sync from the source zone.
Important: Contact IBM Support before running the data sync init command. If you are going for a full restart of sync, and if there is a lot of data that needs to be synced on the source zone, then the bandwidth consumption is high and then you have to plan accordingly.
Note: If a user accidentally deletes a bucket on the secondary site, you can use the metadata sync init command on the site to synchronize data.

Before you begin

  • A running IBM Storage Ceph cluster.
  • Ceph Object Gateway configured at two sites at least.

Procedure

  1. Check the sync status between the sites.
    For example,
    [ceph: host04 /]# radosgw-admin sync status
         realm d713eec8-6ec4-4f71-9eaf-379be18e551b (india)
     zonegroup ccf9e0b2-df95-4e0a-8933-3b17b64c52b7 (shared)
         zone 04daab24-5bbd-4c17-9cf5-b1981fd7ff79 (primary)
 current time 2022-09-15T06:53:52Z
 zonegroup features enabled: resharding
 metadata sync no sync (zone is master)
     data sync source: 596319d2-4ffe-4977-ace1-8dd1790db9fb (secondary)
                         syncing
                         full sync: 0/128 shards
                         incremental sync: 128/128 shards
                         data is caught up with source
  2. Synchronize data from the secondary zone. 
    radosgw-admin data sync init --source-zone primary
    For example,
    [ceph: root@host04 /]# radosgw-admin data sync init --source-zone primary
  3. Restart all the Ceph Object Gateway daemons at the site. 
    ceph orch restart rgw.myrgw