On 18/03/2019 13:24, Brent Kennedy wrote:
I finally received approval to upgrade our old firefly(0.8.7) cluster to
Luminous. I started the upgrade, upgrading to hammer(0.94.10), then
jewel(10.2.11), but after jewel, I ran the “ceph osd crush tunables
optimal” command, then “ceph –s” command showed 60% of the objects were
misplaced. Now the cluster is just churning while it does the recovery
for that.
Is this something that happens when upgrading from firefly up? I had
done a hammer upgrade to Jewel before, no rebalance occurred after
issuing that command.
Any time you change the CRUSH tunables, you can expect data movement.
The exact impact can vary from nothing (if no changes were made or the
changes don't impact your actual pools/CRUSH rules) to a lot of data
movement. This is documented here:
http://docs.ceph.com/docs/master/rados/operations/crush-map/
In particular, you turned on CRUSH_TUNALBLES5, which causes a large
amount of data movement:
http://docs.ceph.com/docs/master/rados/operations/crush-map/#jewel-crush-tunables5
Going from Firefly to Hammer has a much smaller impact (see the CRUSH_V4
section).
--
Hector Martin (hector@xxxxxxxxxxxxxx)
Public Key: https://mrcn.st/pub
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