On 31/08/2020 11:00, Dennis Benndorf wrote:
Hi,
today I recognized bad performance in our cluster. Running "watch ceph osd perf |sort -hk 2 -r" I found that all bluestore OSDs are slow on commit and that the commit timings are equal to their apply timings:
For example Every 2.0s: ceph osd perf |sort -hk 2 -r
440 82 82 430 58 58 435 56 56 449 53 53 442 40 40 441 30 30 439 27 27 99 0 1 98 0 0 97 0 2 96 0 6 95 0 2 94 0 6 93 0 13
The once with zero commit timings are filestore and the others are bluestore osds. I did not see this after installing the new bluestore osds (maybe this occured later). Both types of osds have nvmes as journal/db. Servers have equal cpus/ram etc.
The only tuning regarding bluestore is: bluestore_block_db_size = 69793218560 bluestore_prefer_deferred_size_hdd = 524288 In order to make a filestore like behavior, but that does not seem to work.
As far as I know is that with BlueStore apply and commit latencies are equal. Where did you get the idea that you could influence this with these settings? Wido
Any tips?
Regards Dennis _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io