From my point of view, it's better to have no more than 6 osd wal/db on 1 nvme. I think that's the root cause of the slow requests, maybe.
Mark Kirkwood <mark.kirkw...@catalyst.net.nz> 于2020年6月26日周五 上午7:47写道： > Progress update: > > - tweaked debug_rocksdb to 1/5. *possibly* helped, fewer slow requests > > - will increase osd_memory_target from 4 to 16G, and observe > > On 24/06/20 1:30 pm, Mark Kirkwood wrote: > > Hi, > > > > We have recently added a new storage node to our Luminous (12.2.13) > > cluster. The prev nodes are all setup as Filestore: e.g 12 osds on hdd > > (Seagate Constellations) with one NVMe (Intel P4600) journal. With the > > new guy we decided to introduce Bluestore so it is configured as: > > (same HW) 12 osd with data on hdd and db + wal on one NVMe. > > > > We noticed there are periodic slow requests logged, and the implicated > > osds are the Bluestore ones 98% of the time! This suggests that we > > need to tweak our Bluestore settings in some way. Investigating I'm > > seeing: > > > > - A great deal of rocksdb debug info in the logs - perhaps we should > > tone that down? (debug_rocksdb 4/5 -> 1/5) > > > > - We look to have the default cache settings > > (bluestore_cache_size_hdd|ssd etc), we have memory to increase these > > > > - There are some buffered io settings (bluefs_buffered_io, > > bluestore_default_buffered_write), set to (default) false. Are these > > safe (or useful) to change? > > > > - We have default rocksdb options, should some of these be changed? > > (bluestore_rocksdb_options, in particular max_background_compactions=2 > > - should we have less, or more?) > > > > Also, anything else we should be looking at? > > > > regards > > > > Mark > > > > _______________________________________________ > > ceph-users mailing list -- ceph-users@ceph.io > > To unsubscribe send an email to ceph-users-le...@ceph.io > _______________________________________________ > ceph-users mailing list -- ceph-users@ceph.io > To unsubscribe send an email to ceph-users-le...@ceph.io > _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
