Hello,
your cache tier is working fine, just as you configured it.
On Tue, 27 Jun 2017 16:17:59 +0800 码云 wrote:
> Hi all,When rados put file into pool, the pool usage increase fast, althrough it configured a tier pool.
> I check it with ceph df, USED and OBJECTS columns both increased(both cache pool and base pool).
> But it should't only write into cache tier layer pool?
> pool configure like below:
> jewel 10.2.5, cache pool 2 replications with 3 ssd, base pool 2 replications with 2 hdd.
> cache pool:
> writeback target_bytes 264207763774 target_objects 10000000
> hit_set bloom{false_positive_probability: 0.05, target_size: 0, seed: 0}
> 3600s
> min_read_recency_for_promote 1 min_write_recency_for_promote 1
> cache_target_dirty_ratio:0.4 (current usage percent only 23.47%)
>
And there is your answer, Ceph will not move (flush) objects to the base
pool until that dirty ratio is hit.
Either by size usage or object count.
Christian
>
> NAME ID USED %USED MAX AVAIL OBJECTS
> rbd 0 0 0 30523G 0
> cached_test_cache 5 71625M 23.57 226G 185
> test_cache 6 44324M 1.75 2421G 189
--
Christian Balzer Network/Systems Engineer
chibi@xxxxxxx Rakuten Communications
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