What is your min_size in the cache pool? If your min_size is 2, then the cluster would block requests to that pool due to it having too few copies available.
PS - Please don't consider using rep_size 2 in production.
On Wed, Nov 1, 2017 at 5:14 AM Eugen Block <eblock@xxxxxx> wrote:
Hi experts,
we have upgraded our cluster to Luminous successfully, no big issues
so far. We are also testing cache tier with only 2 SSDs (we know it's
not recommended), and there's one issue to be resolved:
Evertime we have to restart the cache OSDs we get slow requests with
impacts on our client VMs. We never restart both SSDs at the same
time, of course, so we are wondering why the slow requests? What
exactly is happening with a replication size of 2? We assumed that if
one SSD is restarted the data is still available on the other disc, we
didn't expect any problems. But this occurs everytime we have to
restart them. Can anyone explain what is going on there? We could use
your expertise on this :-)
Best regards,
Eugen
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