Ceph » rbd

Useful comment from Ilya:

(In reply to Vasishta from comment #0)

Description of problem:
On a pool where image mode of mirroring enabled, enabling mirroring on an
image in a namespace is falsely failing saying cannot enable mirroring in
the current pool mirroring mode

Hi Vasi,

The failure is legit because mirroring mode is a per-namespace configuration. You can think of the pool itself as just an unnamed namespace. Setting mirroring mode on the pool itself doesn't set it on any of its actual namespaces.

Steps to Reproduce:
1. Configure mirroring between 2 clusters with image mode on a pool
2. Create an image in a namespace.
3. Try to enable mirroring on image

Before attempting to enable mirroring on an image in a namespace, the namespace must have mirroring enabled:

$ rbd mirror pool enable mi_pool/ns_0 image

It can be observed that image mode is enabled on the pool

1. rbd mirror pool info mi_pool
   Mode: image
   Site Name: site-b

Peer Sites:

UUID: 90ba0f6c-f536-48a6-b75a-b8cefa2c59ac
Name: site-a
Mirror UUID: 7f2aec45-a45e-47b8-985f-0243c774b64f
Direction: rx-tx
Client: client.rbd-mirror-peer

... but since it's not enabled on ns_0 namespace, if you had ran "rbd mirror pool info mi_pool/ns_0", you would have gotten "Mode: disabled".