What about drives IOPS ? Hdd tops at an average 150, you can use iostat
-xmt to get these values (also last column show disk utilization which is
very usefull)
On Sun, May 26, 2024, 09:37 Mazzystr <mazzystr@xxxxxxxxx> wrote:
> I can't explain the problem. I have to recover three discs that are hdds.
> I figured on just replacing one to give the full recovery capacity of the
> cluster to that one disc. I was never able to achieve a higher recovery
> rate than about 22 MiB/sec so I just added the other two discs. Recovery
> bounced up to 129 MiB/sec for a while. Then things settled at 50 MiB/sec.
> I kept tinkering to try to get back to 120 and now things are back to 23
> MiB/Sec again. This is very irritating.
>
> Cpu usage is minimal in the single digit %. Mem is right on target per
> target setting in ceph.conf. Disc's and network appear to be 20%
> utilized.
>
> I'm not a normal Ceph user. I don't care about client access at all. The
> mclock assumptions are wrong for me. I want my data to be replicated
> correctly as fast as possible.
>
> How do I open up the floodgates for maximum recovery performance?
>
>
>
>
> On Sat, May 25, 2024 at 8:13 PM Zakhar Kirpichenko <zakhar@xxxxxxxxx>
> wrote:
>
> > Hi!
> >
> > Could you please elaborate what you meant by "adding another disc to the
> > recovery process"?
> >
> > /Z
> >
> >
> > On Sat, 25 May 2024, 22:49 Mazzystr, <mazzystr@xxxxxxxxx> wrote:
> >
> >> Well this was an interesting journey through the bowels of Ceph. I have
> >> about 6 hours into tweaking every setting imaginable just to circle back
> >> to
> >> my basic configuration and 2G memory target per osd. I was never able
> to
> >> exceed 22 Mib/Sec recovery time during that journey.
> >>
> >> I did end up fixing the issue and now I see the following -
> >>
> >> io:
> >> recovery: 129 MiB/s, 33 objects/s
> >>
> >> This is normal for my measly cluster. I like micro ceph clusters. I
> have
> >> a lot of them. :)
> >>
> >> What was the fix? Adding another disc to the recovery process! I was
> >> recovering to one disc now I'm recovering to two. I have three total
> that
> >> need to be recovered. Somehow that one disc was completely swamped. I
> >> was
> >> unable to see it in htop, atop, iostat. Disc business was 6% max.
> >>
> >> My config is back to mclock scheduler, profile high_recovery_ops, and
> >> backfills of 256.
> >>
> >> Thank you everyone that took the time to review and contribute.
> Hopefully
> >> this provides some modern information for the next person that has slow
> >> recovery.
> >>
> >> /Chris C
> >>
> >>
> >>
> >>
> >>
> >> On Fri, May 24, 2024 at 1:43 PM Kai Stian Olstad <ceph+list@xxxxxxxxxx>
> >> wrote:
> >>
> >> > On 24.05.2024 21:07, Mazzystr wrote:
> >> > > I did the obnoxious task of updating ceph.conf and restarting all my
> >> > > osds.
> >> > >
> >> > > ceph --admin-daemon /var/run/ceph/ceph-osd.*.asok config get
> >> > > osd_op_queue
> >> > > {
> >> > > "osd_op_queue": "wpq"
> >> > > }
> >> > >
> >> > > I have some spare memory on my target host/osd and increased the
> >> target
> >> > > memory of that OSD to 10 Gb and restarted. No effect observed. In
> >> > > fact
> >> > > mem usage on the host is stable so I don't think the change took
> >> effect
> >> > > even with updating ceph.conf, restart and a direct asok config set.
> >> > > target
> >> > > memory value is confirmed to be set via asok config get
> >> > >
> >> > > Nothing has helped. I still cannot break the 21 MiB/s barrier.
> >> > >
> >> > > Does anyone have any more ideas?
> >> >
> >> > For recovery you can adjust the following.
> >> >
> >> > osd_max_backfills default is 1, in my system I get the best
> performance
> >> > with 3 and wpq.
> >> >
> >> > The following I have not adjusted myself, but you can try.
> >> > osd_recovery_max_active is default to 3.
> >> > osd_recovery_op_priority is default to 3, a lower number increases the
> >> > priority for recovery.
> >> >
> >> > All of them can be runtime adjusted.
> >> >
> >> >
> >> > --
> >> > Kai Stian Olstad
> >> >
> >> _______________________________________________
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> >>
> >
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