#554 Issue `closed`: mdraid restore issues¶

Labels: support / question

liedekef opened issue at 2015-02-27 14:40:¶

Hi, I'm just trying the latest github version of rear, to be able to restore el6 systems (and the released version gave me issues with /dev/md0, /dev/md1 and parted).
I got this before backup/restore:

# cat /proc/mdstat 
Personalities : [raid1] 
md1 : active raid1 vda2[0] vdb2[1]
      31235520 blocks super 1.1 [2/2] [UU]
      bitmap: 1/1 pages [4KB], 65536KB chunk

md0 : active raid1 vda1[2] vdb1[3]
      205056 blocks super 1.0 [2/2] [UU]

with /dev/md0 being mounted as /boot and the rest in lv-partitions:

# mount
/dev/mapper/vg_00-lv_root on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/md0 on /boot type ext4 (rw)
/dev/mapper/vg_00-lv_home on /home type ext4 (rw)
/dev/mapper/vg_00-lv_opt on /opt type ext4 (rw)
/dev/mapper/vg_00-lv_tmp on /tmp type ext4 (rw)
/dev/mapper/vg_00-lv_usr on /usr type ext4 (rw)
/dev/mapper/vg_00-lv_usropenv on /usr/openv type ext4 (rw)
/dev/mapper/vg_00-lv_var on /var type ext4 (rw)
/dev/mapper/vg_00-lv_varlog on /var/log type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)

Now, after reboot, I got this (I needed to remove an empty line at the top of /etc/fstab and remove the mount of /boot, due to another reason):

# cat /proc/mdstat 
Personalities : [raid1] 
md126 : active (auto-read-only) raid1 vda1[0] vdb1[1]
      255936 blocks super 1.0 [2/2] [UU]

md127 : active raid1 vda2[0] vdb2[1]
      31183872 blocks super 1.1 [2/2] [UU]

unused devices: <none>

As you can see: md0/1 have been renamed to md126/127 (I'm guessing /etc/mdadm.conf is not in the regenerated initramfs). Also, the blkid output is weird:

/dev/vda1: UUID="284ef52b-53eb-43cf-850a-3d56ef840f90" TYPE="ext4"
/dev/vda2: UUID="9806afe8-83df-e9a0-7b0b-af725015303f" UUID_SUB="59b55793-937d-f1a5-c621-43e367d90fd0" LABEL="btcab0001ap:1" TYPE="linux_raid_member"
/dev/vdb1: UUID="533101b7-358c-49c0-ee1c-54e794f3b32d" UUID_SUB="83f0c4d4-73c5-bc0b-f5f1-3b141eb81d42" LABEL="btcab0001ap:0" TYPE="linux_raid_member" 
/dev/vdb2: UUID="9806afe8-83df-e9a0-7b0b-af725015303f" UUID_SUB="ec8a00b6-83db-f783-f65b-7e4494c66c6b" LABEL="btcab0001ap:1" TYPE="linux_raid_member" 
/dev/mapper/vg_00-lv_swap: UUID="b7a1746e-fafa-4d54-8452-13ac74436205" TYPE="swap" 
/dev/mapper/vg_00-lv_root: UUID="327e7579-89bc-4774-bd4e-1da5317ea0da" TYPE="ext4" 
/dev/mapper/vg_00-lv_home: UUID="60a9e1f2-871f-4834-be84-1c8da286d322" TYPE="ext4" 
/dev/mapper/vg_00-lv_usr: UUID="dc44b6ac-8070-4fa0-b9bb-761937b172fe" TYPE="ext4" 
/dev/mapper/vg_00-lv_usropenv: UUID="97d45071-9ff7-4bac-b4c1-c69ffb4a46db" TYPE="ext4" 
/dev/mapper/vg_00-lv_tmp: UUID="6f1347f9-fe3e-43a0-a736-631a5e6c58d6" TYPE="ext4" 
/dev/mapper/vg_00-lv_opt: UUID="bba66e3e-3567-4795-b343-df949f8e3cfb" TYPE="ext4" 
/dev/mapper/vg_00-lv_varlog: UUID="6d6fdb24-67f4-41be-9fc3-79e0a21a6b07" TYPE="ext4" 
/dev/md127: UUID="pmVwqW-wfUi-Ufjd-lXL0-0bUx-ouJO-g8crvV" TYPE="LVM2_member" 
/dev/md126: UUID="284ef52b-53eb-43cf-850a-3d56ef840f90" TYPE="ext4"

As you can see: the blkid of vda2 and vdb2 are the same (which is normal I guess, since they are in a md-raid device). But the blkid of vda1 and vdb1 differ, and the md126 blkid is the same as vda1
This makes me a bit uncomfortable to restore a system of course ...

gdha commented at 2015-02-27 15:54:¶

@liedekef Hi Franky - that is a long time ago (from mkcdrec times I guess)

when you say md0/1 have been renamed to md126/127 was this on the production system itself ? You need to get md stable first I would think...
rear does save the mdadm.conf in its rescue image

liedekef commented at 2015-02-27 18:00:¶

@gdha Hi Gratien. Yep, long time not heard :-)
On the prod system I got md0 and md1 before using rear, so that was stable ... And I did see md0 and md1 during restore, just not after the reboot.
If you need any info, I can give it to you on Monday.

gdha commented at 2015-03-04 19:11:¶

@liedekef could you paste the /var/lib/rear/layout/disklayout.conf file? And a blikid output of the origunal system.

liedekef commented at 2015-03-05 10:38:¶

Gratien: I downloaded the latest git version, re-installed the test system, took a full backup and ran rear on it: this time it seems to be working just fine! More testing to come, but for now this can be closed.

[Export of Github issue for rear/rear.]