I have a failing hard disk (let's call it
sda) which contains, among other things, a 1.5 TB partition (let's call it
sda3). There is another disk (
sdb), which has a 1.5 TB partition (
sdb1) as well. Both used to be part of an mdadm level 1 RAID using metadata version 1.2. Inside this RAID partition (let's call id
md5), there is a LUKS encryption container (let's call it
md5_uncrypted). This container should contain an ext4 partition.
At some place in time around August 10, 2012, I somehow restarted the RAID array with
sdb1 missing and didn't even notice that. When I wanted to replace the RAID yesterday (three months later), I started copying data from
sdb1 until I realized that it was out of date. So I took a look at the old
sda3. By mistake, I ran
mdadm --create instead of
mdadm --assemble to restart
md5 with only
sda3 available. Accordingly, I ignored all warnings and let
mdadm --create continue.
cryptsetup didn't like the content of the new RAID. I didn't actually think
mdadm --create would corrupt data if the same metadata version is used? Well, apparently it did.
I compared the first 20 MB of
sdb1 and noticed that they are equal starting at about 8 MB. So I copied the first 8 MB of
sda3 (I have a backup of the old first 20 MB of
sda3) and tried to assemble
md5 (with only a single drive,
sda3). Unfortunately, this gave me an error:
failed to add /dev/sdb1: Invalid argument
I also tried using the LUKS header from
sdb1 on a freshly
cryptsetup happily did (of course), but it contained garbage.
My question is: Is there any chance to restore at least some of the data from
sda3? Since I have the state from three months ago, everything helps, even just a list of files, or a list of files with modification dates.
# mdadm --examine /dev/sdb1 Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 76a25475:70aa881c:dd30cc93:bbae03b7 Name : ubuntu:0 Creation Time : Fri Mar 16 20:52:16 2012 Raid Level : raid1 Raid Devices : 2 Avail Dev Size : 2930272256 (1397.26 GiB 1500.30 GB) Array Size : 1465129848 (1397.26 GiB 1500.29 GB) Used Dev Size : 2930259696 (1397.26 GiB 1500.29 GB) Data Offset : 2048 sectors Super Offset : 8 sectors State : clean Device UUID : b9012482:afa502cf:7794f4fb:2a0da196 Update Time : Wed Nov 21 20:51:51 2012 Checksum : 4e54a07 - correct Events : 15003 Device Role : Active device 1 Array State : .A ('A' == active, '.' == missing) # mdadm --examine /dev/sda3 Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 54ea031e:42367512:b6a8675b:91f2cb6f Name : willow:5 (local to host willow) Creation Time : Wed Nov 21 18:03:35 2012 Raid Level : raid1 Raid Devices : 2 Avail Dev Size : 2929999872 (1397.13 GiB 1500.16 GB) Array Size : 1464999744 (1397.13 GiB 1500.16 GB) Used Dev Size : 2929999488 (1397.13 GiB 1500.16 GB) Data Offset : 262144 sectors Super Offset : 8 sectors State : active Device UUID : 93c70c36:3cc540a5:13817695:bd4f327c Update Time : Wed Nov 21 18:03:35 2012 Checksum : 321ddb3e - correct Events : 0 Device Role : Active device 1 Array State : .A ('A' == active, '.' == missing)