On Mon, Jun 8, 2020 at 11:42 PM Zhenshi Zhou <deaderzzs@xxxxxxxxx> wrote: > > I have just done a test on rbd-mirror. Follow the steps: > 1. deploy two new clusters, clusterA and clusterB > 2. configure one-way replication from clusterA to clusterB with rbd-mirror > 3. write data to rbd_blk on clusterA once every 5 seconds > 4. get information with 'rbd mirror image status rbd_blk', the "state" is "up+replaying" > 5. demote image on clusterA(just wanna stop syncing and switch client connection to clusterB) > > The result is: > 1. I find that the "last_update" from "rbd mirror image status" updates every 30 seconds, which means I will lose at most 30s of data The status updates are throttled but not the data transfer. > 2. I stopped syncing on 11:02, while the data from rbd_blk on the clusterB is not newer than 10:50. After demotion, you need to promote on the original non-primary side (w/o the --force) option. It won't let you non-force promote unless it has all the data copied. It will continue to copy data while the other side has been demoted until it fully catches up. > > Did I have the wrong steps in the switching progress? > > > > Zhenshi Zhou <deaderzzs@xxxxxxxxx> 于2020年6月9日周二 上午8:57写道： >> >> Well, I'm afraid that the image didn't replay continuously, which means I have some data lost. >> The "rbd mirror image status" shows the image is replayed and its time is just before I demote >> the primary image. I lost about 24 hours' data and I'm not sure whether there is an interval >> between the synchronization. >> >> I use version 14.2.9 and I deployed a one direction mirror. >> >> Zhenshi Zhou <deaderzzs@xxxxxxxxx> 于2020年6月5日周五 上午10:22写道： >>> >>> Thank you for the clarification. That's very clear. >>> >>> Jason Dillaman <jdillama@xxxxxxxxxx> 于2020年6月5日周五 上午12:46写道： >>>> >>>> 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 >>>> > > >> > To unsubscribe send an email to ceph-users-leave@xxxxxxx >>>> > > >> >>>> > > >> >>>> > > >> _______________________________________________ >>>> > > >> ceph-users mailing list -- ceph-users@xxxxxxx >>>> > > >> To unsubscribe send an email to ceph-users-leave@xxxxxxx >>>> > > >> >>>> > > >>>> > > >>>> > > >>>> > > >>>> > _______________________________________________ >>>> > ceph-users mailing list -- ceph-users@xxxxxxx >>>> > To unsubscribe send an email to ceph-users-leave@xxxxxxx >>>> >>>> >>>> >>>> -- >>>> Jason >>>> -- Jason _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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