I did a lot of data movement lately and my observation is, that backfill is very fast (high bandwidth and many thousand keys/s) as long as this is many-to-many OSDs. The number of OSD participating slowly decreases over time until there is only 1 disk left that is written to. This becomes really slow, because the recovery options are for keeping all-to-all under control.
In such a case, you might want to temporarily increase these numbers to something really high (not 10 or 20, but 1000 or 2000; increase in steps) until the single-disk write is over and then set it back again. With SSD this should be OK. Best regards, ================= Frank Schilder AIT Risø Campus Bygning 109, rum S14 ________________________________________ From: Eugen Block <ebl...@nde.ag> Sent: 11 October 2019 10:24 To: Frank Schilder Cc: ceph-users@ceph.io Subject: Re: [ceph-users] Nautilus: PGs stuck remapped+backfilling > You meta data PGs *are* backfilling. It is the "61 keys/s" statement > in the ceph status output in the recovery I/O line. If this is too > slow, increase osd_max_backfills and osd_recovery_max_active. > > Or just have some coffee ... I already had increased osd_max_backfills and osd_recovery_max_active in order to speed things up, and most of the PGs were remapped pretty quick (couple of minutes), but these last 3 PGs took almost two hours to complete, which was unexpected. _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
