After running into issues with running out of kernel memory, I increased the chunksize of my lvmcache from the default (which I believe was 64k) to a much higher 8M.
After this change, blocks do not seem to be promoted to the cache, despite constant use with both reads and writes. The meta cache is being used however (at a roughly similar rate to before the chunksize change). The cache was created in writeback mode.
media-media: 0 46883430400 cache 8 277/2621440 16384 0/56320 0 2903157 0 1259187 0 0 0 1 writeback 2 migration_threshold 2048 smq 0 rw -
Is there a way to investigate why blocks are not being promoted? I understand this large chunk size will likely be a lot less efficient in the general case, but surely some blocks should be promoted?