Universally unique identifier (UUID)

Universally unique identifier (UUID)

• Filesystem UUID
• Block device UUID: lsblk -io KNAME,TYPE,SIZE,MODEL,UUID
• LVM PV UUID: pvdisplay

EXT4 filesystem

mkfs.ext4 /dev/vg01/lv01
mke2fs 1.44.1 (24-Mar-2018)
Creating filesystem with 2441850880 4k blocks and 305233920 inodes
Filesystem UUID: e6742357-a181-4b82-837f-9a01f3e52568
Superblock backups stored on blocks:
	32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
	4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
	102400000, 214990848, 512000000, 550731776, 644972544, 1934917632

Allocating group tables: done
Writing inode tables: done
Creating journal (262144 blocks): done
Writing superblocks and filesystem accounting information: done

LVM

pvdisplay

 --- Physical volume ---
 PV Name               /dev/sdc3
 VG Name               rhvh
 PV Size               <7.28 TiB / not usable 3.00 MiB
 Allocatable           yes
 PE Size               4.00 MiB
 Total PE              1907390
 Free PE               25600
 Allocated PE          1881790
 PV UUID               Tk3lEU-NzHl-miXe-bKNk-wcNN-vvou-nM0IGD

pvcreate --uuid "FmGRh3-zhok-iVI8-7qTD-S5BI-MAEN-NYM5Sk" --restorefile /etc/lvm/archive/VG_00050.vg /dev/sdh1
  Physical volume "/dev/sdh1" successfully created

pvchange --uuid Generate new random UUID for specified PVs.

See also

• Filesystem
• PV: pvcreate, pvchange
• libuuid provided by util-linux package
• multipath, multipathd, mpathpersist, WWIDS, /etc/multipath.conf