Den tis 4 dec. 2018 kl 11:20 skrev Klimenko, Roman <RKlimenko@xxxxxxxxx>: > > Hi everyone! > > On the old prod cluster > - baremetal, 5 nodes (24 cpu, 256G RAM) > - ceph 0.80.9 filestore > - 105 osd, size 114TB (each osd 1.1T, SAS Seagate ST1200MM0018) , raw used 60% > - 15 journals (eash journal 0.4TB, Toshiba PX04SMB040) > - net 20Gbps > - 5 pools, size 2, min_size 1 > we have discovered recently pretty high Average Apply latency, near 20 ms. > Using ceph osd perf I can see that sometimes osd's apply latency could be high as 300-400 ms on some disks. How I can tune ceph in order to reduce this latency? I would start with running "iostat" on all OSDs hosts and see if one or more drives show a huge percent on utilization%. Having one or a few drives that are lots slower than the rest (in many cases it shows up as taking a long time to finish IO and hence more utilization% than the other OSD drives) will hurt the whole cluster speed. If you find one or a few drives being extra slow, lower crush weight so data moves off them to other healthy drives. -- May the most significant bit of your life be positive. _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
 |