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Hello, I have the same use case as you. After using the same settings as you seems to be running correctly and clearing it self. Will monitor and let you know. Thanks for that. ,Ashley From: David Turner [mailto:drakonstein@xxxxxxxxx]
It doesn't sound like you're actually dealing with slow speeds when you execute the flush/evict commands, just that it isn't keeping your cache as small as you'd expect. What are your cache settings? This is all math and equations. One
of your settings/variables must be off, skewing your result. I use a cache pool in front of an EC pool, because that's still required in Jewel, but I don't need it for any speed performance of the underlying pool. I have my settings so that my pool remains empty pretty much constantly. I have a
friend that has a similar setup, except his files are very likely to be read, modified, rewritten, etc for the next 24 hours once they are written, accessed, etc. Here are my settings for my cache pool `ceph osd pool get {pool_name} all`. Notice my targets are 0 for full_ratio, max_objects, etc. Things stay in the cache because the cache_min_flush_age is 30 minutes and the cache_min_evict_age is
an hour. My friend's settings vary only in that his min_flush_age and min_evict_age are 24 hours and 30 hours respectively. The default action as soon as an object reaches the minimum age is to be flushed and evicted because the target for the cache is to
be completely empty. I wrote over 200GB of data to this EC pool yesterday and today there Is less than 500MB in its cache because of some minor reads that have been happening this morning. The cache pool is regularly 0% full without any intervention. hit_set_type: bloom hit_set_period: 3600 hit_set_count: 1 target_max_objects: 0 target_max_bytes: 2000000000000 cache_target_dirty_ratio: 0 cache_target_dirty_high_ratio: 0.6 cache_target_full_ratio: 0 cache_min_flush_age: 1800 cache_min_evict_age: 3600 min_read_recency_for_promote: 0 min_write_recency_for_promote: 1 On the other hand, if you are using cache tiering for actual performance tuning instead of just to satisfy the demands of an EC pool, then these settings probably don't make much sense for your use case. On Wed, May 17, 2017 at 6:57 AM Ashley Merrick <ashley@xxxxxxxxxxxxxx> wrote:
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