I setup my computer as follows
Fedora 37 kernel 6.0.17-300.fc37.x86_64
lvm2-2.03.11-9.fc37.x86_64
sda - SSD
sdb - SSD
sdc - HDD
sdd - HDD
lvcreate -n root -L50G --type=raid1 rootvg sdc sdd
lvcreate -n rootcache -L10G --type=raid1 rootvg sda sdb
lvcreate -n rootmeta -L20M --type=raid1 rootvg sda sdb
lvconvert --type cache-pool --cachemode writeback --poolmetadata rootmeta rootvg/rootcache
lvconvert --cache --cachepool rootcache rootvg/root
sdb failed and I'm getting the usual "Couldn't find device with uuid" errors
So I thought it would be a good idea to disable caching because it's writeback without a mirror, but it's already disabled ???
lvs -a shows ...
root rootvg Cwi-aoC-p- 50.00g [root-cache_cpool] [root-f37_corig] 5.83 6.58 0.00
[root_corig] rootvg rwi-aoC--- 50.00g 100.00
[root_corig_rimage_0] rootvg iwi-aor--- 50.00g
[root_corig_rimage_1] rootvg iwi-aor--- 50.00g
[root_corig_rmeta_0] rootvg ewi-aor--- 4.00m
[root_corig_rmeta_1] rootvg ewi-aor--- 4.00m
[root-cache_cpool] rootvg Cwi---C-p- 10.00g 5.83 6.58 0.00
[root-cache_cpool_cdata] rootvg Cwi-aor-p- 10.00g 100.00
[root-cache_cpool_cdata_rimage_0] rootvg iwi-aor--- 10.00g
[root-cache_cpool_cdata_rimage_1] rootvg Iwi-aor-p- 10.00g
[root-cache_cpool_cdata_rmeta_0] rootvg ewi-aor--- 4.00m
[root-cache_cpool_cdata_rmeta_1] rootvg ewi-aor-p- 4.00m
[root-cache_cpool_cmeta] rootvg ewi-aor-p- 20.00m 100.00
[root-cache_cpool_cmeta_rimage_0] rootvg iwi-aor--- 20.00m
[root-cache_cpool_cmeta_rimage_1] rootvg Iwi-aor-p- 20.00m
[root-cache_cpool_cmeta_rmeta_0] rootvg ewi-aor--- 4.00m
[root-cache_cpool_cmeta_rmeta_1] rootvg ewi-aor-p- 4.00m
If I look at LV status with lvdisplay, I see that
root, root-cache_cpool_cdata & rootvg/rootcache are available
but rootvg/rootcache is NOT available
# lvdisplay -a rootvg/root-cache_cpool 2>/dev/null
--- Logical volume ---
Internal LV Name root-cache_cpool
VG Name rootvg
LV UUID tb9pyc-ARFp-z2PZ-1OA1-SaZB-cRDw-HFDmGL
LV Write Access read/write
LV Creation host, time pru-ch.internal.booths.org.uk, 2023-01-09 11:13:04 +0100
LV Pool metadata root-cache_cpool_cmeta
LV Pool data root-cache_cpool_cdata
LV Status NOT available
LV Size 10.00 GiB
Current LE 2560
Segments 1
Allocation inherit
Read ahead sectors auto
Is this feature by design to protect data when a writeback cache is no longer mirrored, or is this just a lucky coincidence?
