Red Hat SummitChapter 22. Reviewing CRUSH Tunables
If you have been using Ceph for awhile and you are using an older CRUSH tunables setting such as bobtail, you should investigate setting your CRUSH tunables to optimal.
Note
Resetting your CRUSH tunables may result in significant rebalancing. See the Storage Strategies Guide, Chapter 9, Tunables for additional details on CRUSH tunables.
For example:
ceph osd crush tunables optimal
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