31 Dec
2020
31 Dec
'20
11:32 a.m.
On 12/31/20 4:16 AM, Glen Baars wrote:
Hello Ceph Users,
Since upgrading from Nautilus to Octopus ( cluster started in luminous ) I have been
trying to debug why the RocksDB/WAL is maxing out the SSD drives. ( QD > 32, 12000 read
IOPS, 200 write IOPS ).
From what Nautilus release did you upgrade? If this happens to be a
from a release < 14.2.10 it might be the bluefs buffered io change:
TL;DR: bluefs_buffered_io has been changed to "false" in 14.2.10. It
doesn't use buffer cache in that case, and in certain workloads (i.e.
snap trimming) this seem to have a big impact, even for environments
that have large osd_memory_target.
I would change that back to "true" ("ceph config set osd
bluefs_buffered_io true" should do the trick). This change should be
effective immediately for running daemons.
Gr. Stefan