Hi Matthew,
my colleagues and I can still remember that the values do not change
automatically when you upgrade.
I remember performance problems after an upgrade with old tunables a few
years ago.
But such behaviour may change with the next version.
Meanwhile you get a warning in ceph status if they are not set correctly.
https://docs.ceph.com/en/latest/rados/operations/health-checks/#old-crush-t…
Regards, Joachim
___________________________________
Clyso GmbH - Ceph Foundation Member
support(a)clyso.com
https://www.clyso.com
Am 26.02.2021 um 15:52 schrieb Matthew Vernon:
> Hi,
>
> Having been slightly caught out by tunables on my Octopus upgrade[0],
> can I just check that if I do
> ceph osd crush tunables optimal
>
> That will update the tunables on the cluster to the current "optimal"
> values (and move a lot of data around), but that this doesn't mean
> they'll change next time I upgrade the cluster or anything like that?
>
> It's not quite clear from the documentation whether the next time
> "optimal" tunables change that'll be applied to a cluster where
I've
> set tunables thus, or if tunables are only ever changed by a fresh
> invocation of ceph osd crush tunables...
>
> [I assume the same answer applies to "default"?]
>
> Regards,
>
> Matthew
>
> [0] I foolishly thought a cluster initially installed as Jewel would
> have jewel tunables
>
>