Stefan,
I agree with you about the crush rule, but I truely met the problem for
the cluster,
I set the values large for a quick recover:
osd_recovery_max_active 16
osd_max_backfills 32
Is it a very bad setting?
Kern
On 18/8/2020 下午5:27, Stefan Kooman wrote:
> On 2020-08-18 11:13, Hans van den Bogert wrote:
>> I don't think it might lead to more client slow requests if you set it
>> to 4096 in one step, since there is a cap on how many recovery/backfill
>> requests there can be per OSD at any given time.
>>
>> I am not sure though, but I am happy to be proved wrong by the senior
>> members in this list :)
> Not sure if I qualify for senior, but here are my 2 cents ...
>
> I would argue that you do want to do this in one step. Doing this in
> multiple steps will trigger data movement every time you change pg_num
> (and pgp_num for that matter). Ceph will recalculate a new mapping every
> time you change the pg(p)_num for a pool (or by altering CRUSH rules).
>
> osd_recovery_max_active = 1
> osd_max_backfills = 1
>
> If your cluster can't handle this than I wonder what a disk / host
> failure would trigger.
>
> Some on this list would argue that you also want the following setting
> to avoid client IO starvation:
>
> ceph config set osd osd_op_queue_cut_off high
>
> This is already the default in Octopus.
>
> Gr. Stefan
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