Hi!
We have a small production ceph cluster, based on firefly
release.
It was built using hardware we already have in our site so it
is not "new & shiny",
but works quite good. It was started in 2014.09 as a "proof
of concept" from 4 hosts
with 3 x 1tb osd's each: 1U dual socket Intel 54XX & 55XX
platforms on 1 gbit network.
Now it contains 4x12 osd nodes on shared 10Gbit network. We
use it as a backstore
for running VMs under qemu+rbd.
During migration we temporarily use 1U nodes with 2tb osds
and already face some
problems with uneven distribution. I know, that the best
practice is to use osds of same
capacity, but it is impossible sometimes.
Now we have 24-28 spare 2tb drives and want to increase
capacity on the same boxes.
What is the more right way to do it:
- replace 12x1tb drives with 12x2tb drives, so we will have 2
nodes full of 2tb drives and
other nodes remains in 12x1tb confifg
- or replace 1tb to 2tb drives in more unify way, so every
node will have 6x1tb + 6x2tb drives?
I feel that the second way will give more smooth distribution
among the nodes, and
outage of one node may give lesser impact on cluster. Am I
right and what you can
advice me in such a situation?
