I believe I've recently spent some time with this issue, so I hope this is
helpful. Apologies if it's an unrelated dm/udev/ceph-disk problem.
https://lists.freedesktop.org/archives/systemd-devel/2017-July/039222.html
The above email from last July explains the situation somewhat, with the
outco
Last summer we increased an EC 8+3 pool from 1024 to 2048 PGs on our ~1500 OSD
(Kraken) cluster. This pool contained ~2 petabytes of data at the time.
We did a fair amount of testing on a throwaway pool on the same cluster
beforehand, starting with small increases (16/32/64).
The main observati