fyi, there is an interesting note on disabling the write cache here: https://yourcmc.ru/wiki/index.php?title=Ceph_performance&mobileaction=toggle_view_desktop#Drive_cache_is_slowing_you_down On Wed, Jun 24, 2020 at 9:45 AM Benoît Knecht <bknecht@xxxxxxxxxxxxx> wrote: > > Hi Igor, > > Igor Fedotov wrote: > > for the sake of completeness one more experiment please if possible: > > > > turn off write cache for HGST drives and measure commit latency once again. > > I just did the same experiment with HGST drives, and disabling the write cache > on those drives brought the latency down from about 7.5ms to about 4ms. > > So it seems disabling the write cache across the board would be advisable in > our case. Is it recommended in general, or specifically when the DB+WAL is on > the same hard drive? > > Stefan, Mark, are you disabling the write cache on your HDDs by default? > > Cheers, > > -- > Ben > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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