Re: rbd-mirror sync image continuously or only sync once

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On Thu, Jun 4, 2020 at 3:43 AM Zhenshi Zhou <deaderzzs@xxxxxxxxx> wrote:
>
> My condition is that the primary image being used while rbd-mirror sync.
> I want to get the period between the two times of rbd-mirror transfer the
> increased data.
> I will search those options you provided, thanks a lot :)

When using the original (pre-Octopus) journal-based mirroring, once
the initial sync completes to transfer the bulk of the image data from
a point-in-time dynamic snapshot, any changes post sync will be
replayed continuously from the stream of events written to the journal
on the primary image. The "rbd mirror image status" against the
non-primary image will provide more details about the current state of
the journal replay.

With the Octopus release, we now also support snapshot-based mirroring
where we transfer any image deltas between two mirroring snapshots.
These mirroring snapshots are different from user-created snapshots
and their life-time is managed by RBD mirroring (i.e. they are
automatically pruned when no longer needed). This version of mirroring
probably more closely relates to your line of questioning since the
period of replication is at whatever period you create new mirroring
snapshots (provided your two clusters can keep up).

>
> Eugen Block <eblock@xxxxxx> 于2020年6月4日周四 下午3:28写道:
>
> > The initial sync is a full image sync, the rest is based on the object
> > sets created. There are several options to control the mirroring, for
> > example:
> >
> > rbd_journal_max_concurrent_object_sets
> > rbd_mirror_concurrent_image_syncs
> > rbd_mirror_leader_max_missed_heartbeats
> >
> > and many more. I'm not sure I fully understand what you're asking,
> > maybe you could rephrase your question?
> >
> >
> > Zitat von Zhenshi Zhou <deaderzzs@xxxxxxxxx>:
> >
> > > Hi Eugen,
> > >
> > > Thanks for the reply. If rbd-mirror constantly synchronize changes,
> > > what frequency to replay once? I don't find any options I can config.
> > >
> > > Eugen Block <eblock@xxxxxx> 于2020年6月4日周四 下午2:54写道:
> > >
> > >> Hi,
> > >>
> > >> that's the point of rbd-mirror, to constantly replay changes from the
> > >> primary image to the remote image (if the rbd journal feature is
> > >> enabled).
> > >>
> > >>
> > >> Zitat von Zhenshi Zhou <deaderzzs@xxxxxxxxx>:
> > >>
> > >> > Hi all,
> > >> >
> > >> > I'm gonna deploy a rbd-mirror in order to sync image from clusterA to
> > >> > clusterB.
> > >> > The image will be used while syncing. I'm not sure if the rbd-mirror
> > will
> > >> > sync image
> > >> > continuously or not. If not, I will inform clients not to write data
> > in
> > >> it.
> > >> >
> > >> > Thanks. Regards
> > >> > _______________________________________________
> > >> > ceph-users mailing list -- ceph-users@xxxxxxx
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> > >>
> > >>
> > >> _______________________________________________
> > >> ceph-users mailing list -- ceph-users@xxxxxxx
> > >> To unsubscribe send an email to ceph-users-leave@xxxxxxx
> > >>
> >
> >
> >
> >
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-- 
Jason
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