We're on 17.2.5 and had the default value (5.2), but changing it didn't seem to impact recovery speed: root@rdx-00:/# ceph config get osd osd_mclock_cost_per_byte_usec_hdd 5.200000 root@rdx-00:/# ceph config show osd.0 osd_op_queue mclock_scheduler root@rdx-00:/# ceph config set osd osd_mclock_cost_per_byte_usec_hdd 0.4 root@rdx-00:/# ceph config get osd osd_mclock_cost_per_byte_usec_hdd 0.400000 root@rdx-00:/# We have about 500TB of misplaced objects moving about so we are keen to speed it up; was there another parameter that needed to be changed too? thanks. On Mon, 22 May 2023 at 23:24, David Orman <ormandj@corenode.com> wrote:
Someone who's got data regarding this should file a bug report, it sounds like a quick fix for defaults if this holds true.
On 17/05/2023 03.07, 胡 玮文 wrote:
Hi Sake,
We are experiencing the same. I set “osd_mclock_cost_per_byte_usec_hdd” to 0.1 (default is 2.6) and get about 15 times backfill speed, without significant affect client IO. This parameter seems calculated wrongly, from
On Sat, May 20, 2023, at 00:59, Hector Martin wrote: the description 5e-3 should be a reasonable value for HDD (corresponding to 200MB/s). I noticed this default is originally 5.2, then changed to 2.6 to increase the recovery speed. So I suspect the original author just convert the unit wrongly, he may want 5.2e-3 but wrote 5.2 in code.
But all this may be not important in the next version. I see the
relevant code is rewritten, and this parameter is now removed.
high_recovery_ops profile works very poorly for us. It increase the
average latency of client IO from 50ms to about 1s.
Weiwen Hu
Thank you for this, that parameter indeed seems completely wrong (assuming it means what it says on the tin). After changing that my Quincy cluster is no recovering at a much more reasonable speed.
- Hector _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io
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