So i created the brick without the cache an add the cache doing the commands below; but it
appers it's not working because I see no improvement in the benchmarks.
pvcreate /dev/md/VMStorageHot
vgextend RHGS_vg_VMStorage /dev/md/VMStorageHot
lvcreate -L 1500G -n lv_cache RHGS_vg_VMStorage /dev/md/VMStorageHot
lvcreate -L 100M -n lv_cache_meta RHGS_vg_VMStorage /dev/md/VMStorageHot
lvconvert --type cache-pool --cachemode writeback --poolmetadata
RHGS_vg_VMStorage/lv_cache_meta RHGS_vg_VMStorage/lv_cache
lvconvert --type cache --cachepool HGS_vg_VMStorage/lv_cache
RHGS_vg_VMStorage/VMStorage_lv_pool