[ceph-users] Re: resume RBD mirror on another host

On Thu, Jul 13, 2023 at 6:16 PM Tony Liu <tonyliu0592@hotmail.com> wrote:

Hi,

How RBD mirror tracks mirroring process, on local storage? Say, RBD mirror is running on host-1, when host-1 goes down, start RBD mirror on host-2. In that case, is RBD mirror on host-2 going to continue the mirroring?

Hi Tony, No, it's tracked on the RBD image itself -- meaning in RADOS. With journal-based mirroring it's the commit position in the journal (roughly). For snapshot-based mirroring, there is last_copied_object_number field on each mirror snapshot. Thanks, Ilya