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 2. I stopped syncing on 11:02, while the data from rbd_blk on the clusterB is not newer than 10:50. 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 >>> >>> _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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