I just installed a LVM Cache to a RAID1 and it seems it works...

This is what i did:

lvcreate --name lv_cache kujira -L 20G
lvcreate --name lv_cache_meta kujira -L 1G
lvconvert --type cache-pool --poolmetadata kujira/lv_cache_meta kujira/lv_cache
lvconvert --type cache --cachepool kujira/lv_cache kujira/srv

So far so good. But here are a few traps for youngplayers:

1) The Mirrored Volume will not be shown as mirrored when using lvs! Use lvs --all instead to see the mirror status as well. 2) Install the suggested Package thin-provisioning-tools Otherwise /usr/sbin/check_cache can not be found, and the LVM can not be put into active state.

Speedwise I can not say that it much improoves, but I did not tried much things beside a short hdparm -tT...