I have an LVM and I wanted to use bcache to cache one of its LVs. (Yes, I know I could use lvmcache, but I was having issues booting and I gave up using it.)
First, I used blocks to convert the LV to a bcache backing device (this seemed to actually work!):
blocks to-bcache /dev/my_vg/my_lv
I created a caching device on my SSD:
make-bcache --block 4k --bucket 2M -C /dev/sdc4
I then attempted to attach the cache to the backing device:
bcache-super-show /dev/sdc4 | grep cset.uuid
echo 'above_uuid' > /sys/block/bcache0/bcache/attach
I then rebooted my machine (after adding
/etc/fstab) and realized that the cache wasn't running.
# cat /sys/block/bcache0/bcache/state
# bcache-super-show /dev/my_vg/my_lv | grep cache_state
dev.data.cache_state 0 [detached]
Am I missing something? Is there another command I need to use to enable caching?
Why does bcache not like my cache device and not letting me attach it to my backing device? Did I use the wrong values for