I did the same, 1 or 2 years ago, creating a replicated_ruleset_hdd and
replicated_ruleset_ssd. Eventhough I did not have any ssd's on any of
the nodes at that time, adding this hdd type criteria made pg's migrate.
I thought it was strange that this happens on a hdd only cluster, so I
mentioned it here. I am not sure however if this is still an issue, but
better take this into account.
-----Original Message-----
To: ceph-users(a)ceph.io
Subject: [ceph-users] New pool with SSD OSDs
Hello!
We have a Ceph cluster with 30 HDD 4 TB in 6 hosts, only for RBD.
Now, we're receiving other 6 servers with 6 SSD 2 TB each and we want to
create a separate pool for RBD on SSD, and let unused and backup volumes
stays in HDD.
I have some questions:
As I am only using "replicated_rule". ¿If I add an SSD OSD to the
cluster, Ceph starts to migrate PGs to it?
If so, to prevent this, first I have to create rule like
# ceph osd crush rule create-replicated pool-hdd default host hdd
and then
#ceph osd pool set rbd crush_rule pool-hdd
?
Or, if Ceph does not mix automatically hdd and ssd, I create the SSD OSD
and then
# ceph osd crush rule create-replicated pool-ssd default host ssd
# ceph osd pool create pool-ssd 256 256 ssdpool
?
And then migrate images from one to another pool as needed.
Any thoughts are wellcome!
Thanks in advanced for your time.
Javier.-