Description of problem: Create a RO origin (slow) volume lvcreate -p r -L 4G -n corigin cache_sanity /dev/sdb1 WARNING: "cache_sanity/corigin" not zeroed Create a RO cache data and cache metadata (fast) volumes lvcreate -p r -L 2G -n display_cache cache_sanity /dev/sde1 WARNING: "cache_sanity/display_cache" not zeroed lvcreate -p r -L 8M -n display_cache_meta cache_sanity /dev/sde1 WARNING: "cache_sanity/display_cache_meta" not zeroed [root@host-012 ~]# lvs -a -o +devices LV VG Attr LSize Pool Origin Devices corigin cache_sanity -ri-a----- 4.00g /dev/sdb1(0) display_cache cache_sanity -ri-a----- 2.00g /dev/sde1(0) display_cache_meta cache_sanity -ri-a----- 8.00m /dev/sde1(512) [root@host-012 ~]# lvconvert --type cache-pool --cachemode writeback --poolmetadata cache_sanity/display_cache_meta cache_sanity/display_cache /dev/cache_sanity/display_cache_meta: write failed after 0 of 4096 at 0: Operation not permitted Logical volume "lvol0" created Converted cache_sanity/display_cache to cache pool. [root@host-012 ~]# echo $? 0 [root@host-012 ~]# lvconvert --type cache --cachepool cache_sanity/display_cache cache_sanity/corigin device-mapper: reload ioctl on failed: Block device required Device '/dev/sdc1' has been left open. Device '/dev/sda1' has been left open. Device '/dev/sdb1' has been left open. Device '/dev/sda1' has been left open. Device '/dev/sdc1' has been left open. Device '/dev/sdc1' has been left open. Device '/dev/sdb1' has been left open. Device '/dev/sde1' has been left open. Device '/dev/sdb1' has been left open. Device '/dev/sde1' has been left open. Device '/dev/sde1' has been left open. Device '/dev/sda1' has been left open. Device '/dev/sdb1' has been left open. Device '/dev/sdc1' has been left open. Device '/dev/sda1' has been left open. Device '/dev/sde1' has been left open. [root@host-012 ~]# lvs -a -o +devices LV VG Attr LSize Pool Origin Devices corigin cache_sanity -ri-a----- 4.00g /dev/sdb1(0) display_cache cache_sanity Cwi-a-C--- 2.00g display_cache_cdata(0) [display_cache_cdata] cache_sanity Cri-a-C--- 2.00g /dev/sde1(0) [display_cache_cmeta] cache_sanity eri-a-C--- 8.00m /dev/sde1(512) [lvol0_pmspare] cache_sanity ewi------- 8.00m /dev/sda1(0) Jun 18 18:24:50 host-012 kernel: device-mapper: cache metadata: sb_check failed: blocknr 18446744073709551615: wanted 0 Jun 18 18:24:50 host-012 kernel: device-mapper: block manager: superblock validator check failed for block 0 Jun 18 18:24:50 host-012 kernel: device-mapper: cache metadata: couldn't read lock superblock Jun 18 18:24:50 host-012 kernel: device-mapper: table: 253:2: cache: Error creating metadata object Version-Release number of selected component (if applicable): 3.10.0-123.el7.x86_64 lvm2-2.02.105-14.el7 BUILT: Wed Mar 26 08:29:41 CDT 2014 lvm2-libs-2.02.105-14.el7 BUILT: Wed Mar 26 08:29:41 CDT 2014 lvm2-cluster-2.02.105-14.el7 BUILT: Wed Mar 26 08:29:41 CDT 2014 device-mapper-1.02.84-14.el7 BUILT: Wed Mar 26 08:29:41 CDT 2014 device-mapper-libs-1.02.84-14.el7 BUILT: Wed Mar 26 08:29:41 CDT 2014 device-mapper-event-1.02.84-14.el7 BUILT: Wed Mar 26 08:29:41 CDT 2014 device-mapper-event-libs-1.02.84-14.el7 BUILT: Wed Mar 26 08:29:41 CDT 2014 device-mapper-persistent-data-0.3.2-1.el7 BUILT: Thu Apr 3 09:58:51 CDT 2014 cmirror-2.02.105-14.el7 BUILT: Wed Mar 26 08:29:41 CDT 2014