On 25/05/2023 01.40, 胡 玮文 wrote: > Hi Hector, > > Not related to fragmentation. But I see you mentioned CephFS, and your OSDs > are at high utilization. Is your pool NEAR FULL? CephFS write performance is > severely degraded if the pool is NEAR FULL. Buffered write will be disabled, > and every single write() system call needs to wait for reply from OSD. > > If this is the case, use “ceph osd set-nearfull-ratio” to get normal > performance. >
I learned about this after the issue; they did become nearfull at one point and I changed the threshold, but I don't think this explains the behavior I was seeing because I was trying to do bulk writes (which should use very large write sizes even without buffering). What happened was usually a single OSD would immediately go to 100% utilization, but not the rest, which is what I'd expect if that one OSD was the one with the most fragmented free space ending up pathologically slowing down writes. - Hector _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
