Hi, I have a Ceph 16.2.12 cluster with hybrid OSDs (HDD block storage, DB/WAL on NVME). All OSD settings are default except, cache-related settings are as follows: osd.14 dev bluestore_cache_autotune true osd.14 dev bluestore_cache_size_hdd 4294967296 osd.14 dev bluestore_cache_size_ssd 4294967296 osd.14 advanced bluestore_default_buffered_write false osd.14 dev osd_memory_cache_min 2147483648 osd.14 basic osd_memory_target 17179869184 Other settings such as bluestore_cache_kv_ratio, bluestore_cache_meta_ratio, etc. are default. I.e. OSD memory target is set to 16 GB, bluestore cache is set to 4 GB for HDDs and SSDs, minimum cache size is 2 GB. When I dump memory pools of OSDs, bluestore cache doesn't seem to be actively used (https://pastebin.com/EpfFp85C), despite there's plenty of memory and the memory target is 16 GB, memory pools are around 2 GB and the total RSS of the OSD process is ~4.8 GB. There are 66 OSDs in the cluster and the situation is very similar with all of them. The OSDs are being used quite actively for both reads and writes, and I guess they could benefit from using more memory for caching, especially considering that we have lots of RAM available on each host. Is there a way to increase and/or tune OSD cache memory usage? I would appreciate any advice or pointers. Best regards, Zakhar