Ceph RBD mirroring

Jan 4, 2017 · 1 min read · CEPH RBD ·

Check replication

See how much journal data is yet to be replicated, where 'sas' is the pool containing the journal data

1rados ls -p sas | grep journal | wc -l

Enable mirroring for an image

Step 1 - Enable journaling feature for the image(You can place the journal data on a separate pool)

1rbd feature enable sas/ADLWest-R3.raw journaling

Check to see if the journaling flag has applied

 1[root@adleast-cephreplica ~]# rbd info sas/ADLWest-R3.raw
 2rbd image 'ADLWest-R3.raw':
 3        size 128 MB in 32 objects
 4        order 22 (4096 kB objects)
 5        block_name_prefix: rbd_data.2e931f238e1f29
 6        format: 2
 7        features: layering, exclusive-lock<, object-map, fast-diff, deep-flatten, journaling
 8        flags:
 9        journal: 2e931f238e1f29
10        mirroring state: disabled

Enable mirroring

1rbd mirror image enable sas/ADLWest-R3.raw

Check to see if mirroring has applied

 1[root@adleast-cephreplica ~]# rbd info sas/ADLWest-R3.raw
 2rbd image 'ADLWest-R3.raw':
 3        size 128 MB in 32 objects
 4        order 22 (4096 kB objects)
 5        block_name_prefix: rbd_data.2e931f238e1f29
 6        format: 2
 7        features: layering, exclusive-lock, object-map, fast-diff, deep-flatten, journaling
 8        flags:
 9        journal: 2e931f238e1f29
10        mirroring state: enabled
11        mirroring global id: 1c590dca-9123-4613-95d8-2267338f4e8a
12        mirroring primary: true