On Fri, Jul 26, 2019 at 1:02 PM Peter Sabaini <peter@xxxxxxxxxx> wrote:
On 26.07.19 15:03, Stefan Kooman wrote:
> Quoting Peter Sabaini (peter@xxxxxxxxxx):
>> What kind of commit/apply latency increases have you seen when adding a
>> large numbers of OSDs? I'm nervous how sensitive workloads might react
>> here, esp. with spinners.
>
> You mean when there is backfilling going on? Instead of doing "a big
Yes exactly. I usually tune down max rebalance and max recovery active
knobs to lessen impact but still I found the additional write load can
substantially increase i/o latencies. Not all workloads like this.
We have been using:
osd op queue cut off = high
It virtually eliminates the impact of backfills on our clusters. Our backfill and recovery times have increased when the cluster has lots of client I/O, but the clients haven't noticed that huge backfills have been going on.
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Robert LeBlanc
PGP Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1
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