> >> [osd] >> bluestore_cache_autotune = 0 > > Why are you turning autotuning off? FWIW I’ve encountered the below assertions. I neither support nor deny them, pasting here for discussion. One might interpret this to only apply to OSDs with DB on a seperate (faster) device. >>> With random small block workloads, it’s important to keep BlueStore metadata cached and keep RocksDB from spilling over to slow media – including during compaction. If there is adequate memory on the OSD node, it is recommended to increase the BlueStore metadata cache ratio. An example of this is shown below: >>> >>> bluestore_cache_meta_ratio = 0.8 >>> bluestore_cache_kv_ratio = 0.2 >>> osd bluestore_cache_size_ssd 6GB >>> >>> In Ceph Nautilus and above, the cache ratios are automatically tuned so it is recommended to first observe the relevant cache hit counters in BlueStore before manually setting these parameters. There is some disagreement regarding how effective the auto tuning is. >>> >>>> https://ceph.io/community/bluestore-default-vs-tuned-performance-comparison/ suggests that we still set >>>> >>>> bluestore_cache_size_ssd = 8GB with 12GB memory target. _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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