Den fre 30 aug. 2019 kl 10:49 skrev Amudhan P <amudha...@gmail.com>: > After leaving 12 hours time now cluster status is healthy, but why did it > take such a long time for backfill? > How do I fine-tune? if in case of same kind error pop-out again. > > The backfilling is taking a while because max_backfills = 1 and you only >> have 3 OSD's total so the backfilling per PG has to have for the previous >> PG backfill to complete. >> >> That setting is the main tuning, EXCEPT it will be at the expense of client traffic, so you can allow a large(r) amount of parallel recoveries and backfills, but of course it will be more noticeable for your client IO if you do.
Lastly, getting backfill MB/s up is "best" done by having a huge amount of OSD hosts, and fast OSD drives and let the cluster work in parallel, as opposed to having 3 drives only because you will see no parallelism on that setup (if you have size=3 all OSDs are always involved in every single PG to recover) and you will just see overhead compare to what disk-read and disk-write would give on a single drive. -- May the most significant bit of your life be positive.
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