Hi,

I'm still trying to fight large Ceph monitor writes. One option I
considered is enabling RocksDB compression, as our nodes have more than
sufficient RAM and CPU. Unfortunately, monitors seem to completely ignore
the compression setting:

I tried:

- setting ceph config set mon.ceph05 mon_rocksdb_options
"write_buffer_size=33554432,compression=kLZ4Compression,level_compaction_dynamic_level_bytes=true",
restarting the test monitor. The monitor started with no RocksDB
compression:

debug 2023-10-13T19:47:00.403+0000 7f1cd967a880  4 rocksdb: Compression
algorithms supported:
debug 2023-10-13T19:47:00.403+0000 7f1cd967a880  4 rocksdb:
kZSTDNotFinalCompression supported: 0
debug 2023-10-13T19:47:00.403+0000 7f1cd967a880  4 rocksdb:
kXpressCompression supported: 0
debug 2023-10-13T19:47:00.403+0000 7f1cd967a880  4 rocksdb:
kLZ4HCCompression supported: 1
debug 2023-10-13T19:47:00.403+0000 7f1cd967a880  4 rocksdb:
kLZ4Compression supported: 1
debug 2023-10-13T19:47:00.403+0000 7f1cd967a880  4 rocksdb:
kBZip2Compression supported: 0
debug 2023-10-13T19:47:00.403+0000 7f1cd967a880  4 rocksdb:
kZlibCompression supported: 1
debug 2023-10-13T19:47:00.403+0000 7f1cd967a880  4 rocksdb:
kSnappyCompression supported: 1
...
debug 2023-10-13T19:47:00.403+0000 7f1cd967a880  4 rocksdb:
 Options.compression: NoCompression
debug 2023-10-13T19:47:00.403+0000 7f1cd967a880  4 rocksdb:
 Options.bottommost_compression: Disabled

- setting ceph config set mon mon_rocksdb_options
"write_buffer_size=33554432,compression=kLZ4Compression,level_compaction_dynamic_level_bytes=true",
restarting the test monitor. The monitor started with no RocksDB
compression, the same way as above.

In each case config options were correctly set and readable with config
get. I also found a suggestion in ceph-users (
https://lists.ceph.io/hyperkitty/list/ceph-users@ceph.io/message/KJM232IHN7FKYI5LODUREN7SVO45BL42/)
to set compression in a similar manner. Unfortunately, these options appear
to be ignored.

How can I enable RocksDB compression in Ceph monitors?

I would very much appreciate your advices and comments.

Best regards,
Zakhar
_______________________________________________
ceph-users mailing list -- ceph-users@ceph.io
To unsubscribe send an email to ceph-users-le...@ceph.io

Reply via email to