On Mon, Nov 22, 2021 at 4:52 PM Nico Schottelius <nico.schottelius@xxxxxxxxxxx> wrote: > > > Peter Lieven <pl@xxxxxxx> writes: > > Whatever SSD you choose, look if they support power-loss-protection and make sure you disable the write cache. > > I have read this statement multiple times now, but I am still puzzled by > the disabling write cache statement. What is wrong with having a (BBU > based) write cache in front of the SSDs / how does it decrease the > perfomance? > > As far as I can tell, this is just another buffer/cache that is added in > the write chain and thus should improve speed for small writes. For > write bursts / longer writes the cache will not play a role anymore. > > What am I missing? This: https://github.com/ceph/ceph/pull/43848/files https://yourcmc.ru/wiki/Ceph_performance#Drive_cache_is_slowing_you_down -- dan _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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