Hello, I apologize for replying to my own message, I was subscribed in the digest mode... I've been hitting my head against this one for a while now. Originally discovered this on Ubuntu 20.04, but I'm seeing the same issue with RHEL 8.5. The loss of a single disk leaves the RAID in "partial" mode, when it should be "degraded". I've tried to explicitly specify the number of stripes, but it did not make a difference. After adding the missing disk back, the array is healthy again. Please see below. # cat /etc/redhat-release Red Hat Enterprise Linux release 8.5 (Ootpa) # lvm version LVM version: 2.03.12(2)-RHEL8 (2021-05-19) Library version: 1.02.177-RHEL8 (2021-05-19) Driver version: 4.43.0 # lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 50G 0 disk ├─sda1 8:1 0 1G 0 part /boot └─sda2 8:2 0 49G 0 part ├─rhel-root 253:0 0 44G 0 lvm / └─rhel-swap 253:1 0 5G 0 lvm [SWAP] sdb 8:16 0 70G 0 disk sdc 8:32 0 100G 0 disk sdd 8:48 0 100G 0 disk sde 8:64 0 100G 0 disk sdf 8:80 0 100G 0 disk sdg 8:96 0 100G 0 disk # pvcreate /dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg # vgcreate pool_vg /dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg # lvcreate -l +100%FREE -n pool_lv --type raid6 --stripes 3 --stripesize 1 pool_vg Invalid stripe size 1.00 KiB. Run `lvcreate --help' for more information. # lvcreate -l +100%FREE -n pool_lv --type raid6 --stripes 3 --stripesize 4 pool_vg Logical volume "pool_lv" created. # mkfs.xfs /dev/pool_vg/pool_lv # echo "/dev/mapper/pool_vg-pool_lv /mnt xfs defaults,x-systemd.mount-timeout=30 0 0" >> /etc/fstab # mount -a # touch /mnt/test Note the RAID is correctly striped across all 5 disks: # lvs -a -o name,lv_attr,copy_percent,health_status,devices pool_vg LV Attr Cpy%Sync Health Devices pool_lv rwi-aor--- 100.00 pool_lv_rimage_0(0),pool_lv_rimage_1(0),pool_lv_rimage_2(0),pool_lv_rimage_3(0),pool_lv_rimage_4(0) [pool_lv_rimage_0] iwi-aor--- /dev/sdc(1) [pool_lv_rimage_1] iwi-aor--- /dev/sdd(1) [pool_lv_rimage_2] iwi-aor--- /dev/sde(1) [pool_lv_rimage_3] iwi-aor--- /dev/sdf(1) [pool_lv_rimage_4] iwi-aor--- /dev/sdg(1) [pool_lv_rmeta_0] ewi-aor--- /dev/sdc(0) [pool_lv_rmeta_1] ewi-aor--- /dev/sdd(0) [pool_lv_rmeta_2] ewi-aor--- /dev/sde(0) [pool_lv_rmeta_3] ewi-aor--- /dev/sdf(0) [pool_lv_rmeta_4] ewi-aor--- /dev/sdg(0) After shutting down the OS and removing a disk, reboot drops the system into a single user mode because it cannot mount /mnt! The RAID is now in "partial" mode, when it must be just "degraded". # lvs -a -o name,lv_attr,copy_percent,health_status,devices pool_vg WARNING: Couldn't find device with uuid d5y3gp-taRv-2YMa-3mR0-94ZZ-72Od-IKF8Co. WARNING: VG pool_vg is missing PV d5y3gp-taRv-2YMa-3mR0-94ZZ-72Od-IKF8Co (last written to /dev/sdc). LV Attr Cpy%Sync Health Devices pool_lv rwi---r-p- partial pool_lv_rimage_0(0),pool_lv_rimage_1(0),pool_lv_rimage_2(0),pool_lv_rimage_3(0),pool_lv_rimage_4(0) [pool_lv_rimage_0] Iwi---r-p- partial [unknown](1) [pool_lv_rimage_1] Iwi---r--- /dev/sdc(1) [pool_lv_rimage_2] Iwi---r--- /dev/sdd(1) [pool_lv_rimage_3] Iwi---r--- /dev/sde(1) [pool_lv_rimage_4] Iwi---r--- /dev/sdf(1) [pool_lv_rmeta_0] ewi---r-p- partial [unknown](0) [pool_lv_rmeta_1] ewi---r--- /dev/sdc(0) [pool_lv_rmeta_2] ewi---r--- /dev/sdd(0) [pool_lv_rmeta_3] ewi---r--- /dev/sde(0) [pool_lv_rmeta_4] ewi---r--- /dev/sdf(0) After adding the missing disk back, the system boots correctly and there are no issues with the RAID: # lvs -a -o name,lv_attr,copy_percent,health_status,devices pool_vg LV Attr Cpy%Sync Health Devices pool_lv rwi-a-r--- 100.00 pool_lv_rimage_0(0),pool_lv_rimage_1(0),pool_lv_rimage_2(0),pool_lv_rimage_3(0),pool_lv_rimage_4(0) [pool_lv_rimage_0] iwi-aor--- /dev/sdc(1) [pool_lv_rimage_1] iwi-aor--- /dev/sdd(1) [pool_lv_rimage_2] iwi-aor--- /dev/sde(1) [pool_lv_rimage_3] iwi-aor--- /dev/sdf(1) [pool_lv_rimage_4] iwi-aor--- /dev/sdg(1) [pool_lv_rmeta_0] ewi-aor--- /dev/sdc(0) [pool_lv_rmeta_1] ewi-aor--- /dev/sdd(0) [pool_lv_rmeta_2] ewi-aor--- /dev/sde(0) [pool_lv_rmeta_3] ewi-aor--- /dev/sdf(0) [pool_lv_rmeta_4] ewi-aor--- /dev/sdg(0) On Tue, Jan 25, 2022 at 11:44 AM Andrei Rodionov <andrei.rodionov@xxxxxxxxx> wrote: > > Hello, > > I've provisioned an LVM RAID 6 across 5 physical disks. I'm trying to understand the RAID behavior after injecting the failure - removing physical disk /dev/sdc. _______________________________________________ linux-lvm mailing list linux-lvm@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
