Hello (again)
Sorry to resuscitate this topic back from the dead, but I have again the
same issue.
TL;DR
The difference compared to last time:
- I created a clean raid a few days back
- the data is completely backed up and available
- I can actually access the data
but I still have no clue about what went wrong.
1) I created the raid:
sudo mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3
/dev/sdb /dev/sdc /dev/sdd
without lvm this time, juste a single ext4 partition
mkfs.ext4 /dev/md0
mount /dev/md0 /srv/data
I copied 3Tb on it
I just rebooted the machine
2) and (again) no md0 assembled at boot:
mdadm -E /dev/sd[bcd]
/dev/sdb:
MBR Magic : aa55
Partition[0] : 4294967295 sectors at 1 (type ee)
/dev/sdc:
MBR Magic : aa55
Partition[0] : 4294967295 sectors at 1 (type ee)
/dev/sdd:
MBR Magic : aa55
Partition[0] : 4294967295 sectors at 1 (type ee)
This time, I am able to get my data back. I first create the overlays and:
mdadm --create --verbose /dev/md0 --assume-clean --level=5
--raid-devices=3 /dev/mapper/sdb /dev/mapper/sdc /dev/mapper/sdd
mount /dev/md0 /srv/data
# mdadm --detail --scan /dev/md0
ARRAY /dev/md0 metadata=1.2 name=smic:0
UUID=2ebab32e:82283ac5:4232d2ee:92abf170
and it mounts, so I did exactly the same using the real disks and
(again) got my data back. The raid is now running:
# mdadm -E /dev/sdb
/dev/sdb:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : 2ebab32e:82283ac5:4232d2ee:92abf170
Name : smic:0 (local to host smic)
Creation Time : Mon Jul 31 21:36:12 2017
Raid Level : raid5
Raid Devices : 3
Avail Dev Size : 5860271024 (2794.40 GiB 3000.46 GB)
Array Size : 5860270080 (5588.79 GiB 6000.92 GB)
Used Dev Size : 5860270080 (2794.39 GiB 3000.46 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262056 sectors, after=944 sectors
State : clean
Device UUID : 2d1daf78:1e085799:6f1799b2:e88e60d1
Internal Bitmap : 8 sectors from superblock
Update Time : Mon Jul 31 21:36:19 2017
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 63abce91 - correct
Events : 1
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 0
Array State : AAA ('A' == active, '.' == missing, 'R' == replacing)
# mdadm -E /dev/sdc
/dev/sdc:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : 2ebab32e:82283ac5:4232d2ee:92abf170
Name : smic:0 (local to host smic)
Creation Time : Mon Jul 31 21:36:12 2017
Raid Level : raid5
Raid Devices : 3
Avail Dev Size : 5860271024 (2794.40 GiB 3000.46 GB)
Array Size : 5860270080 (5588.79 GiB 6000.92 GB)
Used Dev Size : 5860270080 (2794.39 GiB 3000.46 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262056 sectors, after=944 sectors
State : clean
Device UUID : db6d0696:072c5166:1491157d:6ddf34cf
Internal Bitmap : 8 sectors from superblock
Update Time : Mon Jul 31 21:36:19 2017
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 164e0d53 - correct
Events : 1
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 1
Array State : AAA ('A' == active, '.' == missing, 'R' == replacing)
# mdadm -E /dev/sdd
/dev/sdd:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : 2ebab32e:82283ac5:4232d2ee:92abf170
Name : smic:0 (local to host smic)
Creation Time : Mon Jul 31 21:36:12 2017
Raid Level : raid5
Raid Devices : 3
Avail Dev Size : 5860271024 (2794.40 GiB 3000.46 GB)
Array Size : 5860270080 (5588.79 GiB 6000.92 GB)
Used Dev Size : 5860270080 (2794.39 GiB 3000.46 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262056 sectors, after=944 sectors
State : clean
Device UUID : 0c52bea6:a0cbf060:fe5edff0:4ee71d21
Internal Bitmap : 8 sectors from superblock
Update Time : Mon Jul 31 21:36:19 2017
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : e75866e8 - correct
Events : 1
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 2
Array State : AAA ('A' == active, '.' == missing, 'R' == replacing)
but a reboot always brings me back to step 2), with the need to press
ctrl-D at boot time.
What am I missing? Am I using a bad version of the mdadm or kernel
(mdadm:amd64 3.3.2-5+deb8u2, kernel 4.8.0-0.bpo.2-amd64) or am I doing
it wrong in another way ?
best regards,
On 06/10/2017 10:41 PM, Andreas Klauer wrote:
On Sat, Jun 10, 2017 at 10:04:16PM +0200, Paul Tonelli wrote:
I believe the offset we manually specify is after the default one on a
raid assembly with 3 disks, so it should have rebuilt the previous LVM
superblock, or am I missing something (again).
It should be the reverse. When you grow the raid, the offset shrinks.
Not able to provide further insights. You have a LVM2 header which,
given the correct offset, should appear on the /dev/md device and
in that case everything else should appear too.
If that is not the case then things will be a lot more complicated.
Regards
Andreas Klauer
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