It claimed error when I promoted the non-primary image at first. But the command executed successfully after a while, without '--force'. error: "rbd: error promoting image to primary2020-06-09 19:56:30.662 7f27e17fa700 -1 librbd::mirror::PromoteRequest: 0x558fa971fd20 handle_get_info: image is still primary within a remote cluster 2020-06-09 19:56:30.662 7f2804362b00 -1 librbd::api::Mirror: image_promote: failed to promote image" Besides that, I wrote data by adding `date` to the end of a file, and flushed data by 'echo 3 > /proc/sys/vm/drop_caches'. Jason Dillaman <jdillama@xxxxxxxxxx> 于2020年6月9日周二 下午7:48写道： > On Tue, Jun 9, 2020 at 7:26 AM Zhenshi Zhou <deaderzzs@xxxxxxxxx> wrote: > > > > I did promote the non-primary image, or I couldn't disable the image > mirror. > > OK, that means that 100% of the data was properly transferred since it > needs to replay previous events before it can get to the demotion > event, replay that, so that you could non-force promote. How are you > writing to the original primary image? Are you flushing your data? > > > Jason Dillaman <jdillama@xxxxxxxxxx> 于2020年6月9日周二 下午7:19写道： > >> > >> 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 > >> > > > -- > Jason > > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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