4 Sep
2019
4 Sep
'19
1:31 p.m.
Wed, 4 Sep 2019 10:32:56 +0200
Yoann Moulin <yoann.moulin(a)epfl.ch> ==> ceph-users(a)ceph.io :
Hello,
I'm still unsure with the size of the block.db and the wal.
This seems to be relevant:
http://lists.ceph.com/pipermail/ceph-users-ceph.com/2019-May/035086.html
But it is also said that the pure WAL need just 1 GB of space.
http://lists.ceph.com/pipermail/ceph-users-ceph.com/2019-August/036509.html
So the conclusion would be to use 2*X(DB) + 1GB (WAL) if you put both on the same
partition/LV.
With X being on of 3GB, 30GB or 300GB.
You have 10 OSDs. That means you should have 10 partitions/LVs for DBs & WALs.
This is something that should be cleared up in the docs!
Lars
Tue, 3 Sep 2019 11:28:20 +0200
Yoann Moulin <yoann.moulin(a)epfl.ch> ==> ceph-users(a)ceph.io :
What is the recommended size for wall and db in my case?
I have :
10x 6TB Disk OSDs (data)
2x 480G SSD
Best, Is it better to put all WAL on one SSD and all
DBs on the other one? Or put WAL and DB of the first 5 OSDs on the first SSD and the 5
others on
the second one.
I don't know if this has a relevant impact on the latency/speed of the ceph system
but we use LVM on top of a SW RAID 1 over two SSDs for WAL & DB on this RAID1.