Description of problem: When using a thinly provisioned LVM member blkid is unable to detect the filesystem and report data such as UUID Version-Release number of selected component (if applicable): libblkid-2.23.2-33.el7.x86_64 util-linux-2.23.2-33.el7.x86_64 How reproducible: Always Steps to Reproduce: 1. lvcreate -n full -l 10%FREE vg_myvg 2. lvcreate -n tp -T -l 10%FREE vg_myvg 3. mkfs.xfs /dev/vg_myvg/full 4. mkfs.xfs /dev/vg_myvg/tp 5. blkid /dev/vg_myvg/full 6. blkid /dev/vg_myvg/tp Actual results: Nothing returned by blkid Expected results: UUID and type to be returned by blkid, so no difference in behaviour between thinly provisioned and full Additional info: This also behaves the same with other filesystems such as ext4 so is not an xfs issue specifically. Using xfs_admin or dumpe2fs against the TP LVM member does display the expected data.
[root@c7-multidisktest ~]# mount /home/jenkins/ mount: can't find UUID=a99a213f-6af6-4707-a597-6fee02bd2b31 [root@c7-multidisktest ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 20G 0 disk ├─sda1 8:1 0 500M 0 part /boot └─sda2 8:2 0 19.5G 0 part ├─centos_c7--template-root 253:0 0 17.5G 0 lvm / └─centos_c7--template-swap 253:1 0 2G 0 lvm [SWAP] sdb 8:16 0 20G 0 disk └─sdb1 8:17 0 20G 0 part ├─vg_data-jenkins_tmeta 253:2 0 12M 0 lvm │ └─vg_data-jenkins 253:4 0 10G 0 lvm ├─vg_data-jenkins_tdata 253:3 0 10G 0 lvm │ └─vg_data-jenkins 253:4 0 10G 0 lvm └─vg_data-testdata 253:5 0 5G 0 lvm /mnt/testdata1 sdc 8:32 0 60G 0 disk └─sdc1 8:33 0 60G 0 part /mnt/testdata2 [root@c7-multidisktest ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root centos_c7-template -wi-ao---- 17.47g swap centos_c7-template -wi-ao---- 2.00g jenkins vg_data twi-a-tz-- 10.00g 0.00 0.62 testdata vg_data -wi-ao---- 4.98g [root@c7-multidisktest ~]# xfs_admin -u /dev/vg_data/jenkins UUID = a99a213f-6af6-4707-a597-6fee02bd2b31 [root@c7-multidisktest ~]# blkid /dev/vg_data/jenkins [root@c7-multidisktest ~]#
argh bad copy paste overwrite ... comment 2 shows that this bug prevents mounting a thin provisioned LVM member via UUID as well
(In reply to James Hogarth from comment #0) > Description of problem: > When using a thinly provisioned LVM member blkid is unable to detect the > filesystem and report data such as UUID > > Version-Release number of selected component (if applicable): > libblkid-2.23.2-33.el7.x86_64 > util-linux-2.23.2-33.el7.x86_64 > > How reproducible: > Always > > Steps to Reproduce: > 1. lvcreate -n full -l 10%FREE vg_myvg > 2. lvcreate -n tp -T -l 10%FREE vg_myvg > 3. mkfs.xfs /dev/vg_myvg/full > 4. mkfs.xfs /dev/vg_myvg/tp This is not correct. To create thin LV, you need to create thin pool first and then you need to allocate thin LV out of that pool, for example: lvcreate -n thin_pool -L <pool_size_here> -T vg_myvg lvcreate -n thin_lv -V <virtual_thin_lv_size_here> -T vg_myvg/thin_pool
(In reply to James Hogarth from comment #0) ... > 2. lvcreate -n tp -T -l 10%FREE vg_myvg ... > 4. mkfs.xfs /dev/vg_myvg/tp (Here, you wrote directly to thin pool device - you can't do that - thin pool is only for LVM to allocate thin LVs from.)
Note that libblkid explicitly ignores private LVM devices (e.g. pool metadata etc.) -- this is reason why blkid may returns nothing.
*** Bug 1400135 has been marked as a duplicate of this bug. ***