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-tu... Regards, Joachim ___________________________________ Clyso GmbH - Ceph Foundation Member support@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