[pve-devel] ceph replication speed

[Dietmar Maurer]

> size=3:
> When you write to only three OSDs, each one replicates to two more OSDs, a
> total of 9 OSD writes.
> Half of the OSDs make two writes, I would expect reduced performance with
> 50% of the OSDs doing twice the work.
> 
> I suspect if you added three more OSDs then size=3 would perform at
> 100MB/sec and size=2 would be faster than 100MB/sec.

Sound reasonable now. I will test that when the new disk arrive.