On Tue, Mar 10, 2020 at 6:47 AM Ml Ml <mliebherr99@xxxxxxxxxxxxxx> wrote: > > Hello List, > > when i initially enable journal/mirror on an image it gets > bootstrapped to my site-b pretty quickly with 250MB/sec which is about > the IO Write limit. > > Once its up2date, the replay is very slow. About 15KB/sec and the > entries_behind_maste is just running away: > > root@ceph01:~# rbd --cluster backup mirror pool status rbd-cluster6 --verbose > health: OK > images: 3 total > 3 replaying > > ... > > vm-112-disk-0: > global_id: 60a795c3-9f5d-4be3-b9bd-3df971e531fa > state: up+replaying > description: replaying, master_position=[object_number=623, > tag_tid=3, entry_tid=345567], mirror_position=[object_number=35, > tag_tid=3, entry_tid=18371], entries_behind_master=327196 > last_update: 2020-03-10 11:36:44 > > ... > > Write traffic on the source is about 20/25MB/sec. > > On the Source i run 14.2.6 and on the destination 12.2.13. > > Any idea why the replaying is sooo slow? What is the latency between the two clusters? I would recommend increasing the "rbd_mirror_journal_max_fetch_bytes" config setting (defaults to 32KiB) on your destination cluster. i.e. try adding add "rbd_mirror_journal_max_fetch_bytes = 4194304" to the "[client]" section of your Ceph configuration file on the node where "rbd-mirror" daemon is running, and restart it. It defaults to a very small read size from the remote cluster in a primitive attempt to reduce the potential memory usage of the rbd-mirror daemon, but it has the side-effect of slowing down mirroring for links with higher latencies. > > Thanks, > Michael > _______________________________________________ > 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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