Software RAID drive issues

Ask Fedora
1

Hi Forum,

Is anyone any good with mdadm and software RAID who can help me out? Got a load of photos and data I really don’t want to lose on this drive … no back up :frowning:

The machine locked out on me yesterday, it hit 100% CPU so in the end, I had no choice but to press the reset button.

It now will not boot. I have have a go at getting RAID going again through rescue mode, but I couldn’t seem to get the raid array going again.

I have loaded up a Fedora LIVE CD, and the drive was detected straight away, and I can mount it.

However, all the image files on it seemingly won’t open. I get input/output error. What could be causing this? Is there any way to see if its corrupted?

2

cat /proc/mdstat should tell you the status of your RAID array. It is a known shortcoming of mdadm that is doesn’t do checksums of the data when it is configured to mirror drives. ZFS is superior. However, ZFS has a higher learning curve.

3

I’ve run memtestx86 just now in case there was some RAM issue. PASS.

The SMARTtest results for all three drives are PASS.

I did just notice in dmesg when I mount the raid drive …

ext4)clear_journal)err:6271: Filesystem error recorded from previous mount: IO failure
ext4)clear_journal)err:6279: Marked fs in need of filesystem check,

Then it says …

warning: mounting fs with errors, running e2fsck recommended
recovery complete

Then I can view a few files seemingly with the file browser. Then it suddenly won’t ready them any more.

Now this in dmesg …

inode_doinit_use_xattr: getxattr: getxattr returned 5 for dev=dm-0 ino=109blah

4

MDRAID protects against disk failures, but not necessarily filesystem errors. There might not be much you can do with ext4. If the RAID array is assembling correctly, use dd to make a backup copy of it and then try using ext4’s e2fsck and hope for the best.

5

Well what do you know, fsck has fixed it! I don’t think it was ever anything to do with RAID or a failing drive, it was “just” file system corruption.

It does make me think I ought to get some other sort of backup in place. Not sure what’s suitable for a home server.

Totally threw me off that seemingly RAID 5 is not supported in Fedora rescue mode? Switching to the livecd got me closer to on the right track.

I also noticed a warning on boot about initramfs being EOL? I now know what that is after all this. I need to look into that too.

6

I’ve seen that EOL message a few times as well. I think it was erroneous a few times (it was showing for a release of Fedora Linux that was not yet EOL). It is just an advisory that you should update your Fedora Linux installation (or at least the kernel version that you are using).

P.S. A log based filesystem like Btrfs or ZFS will make backups much easier and more efficient. They can do snapshots and send them incrementally (only the data that has changed) to a backup device. If you also want RAID, I would recommend ZFS. I’ve heard that Btrfs’ RAID implementation is (currently) unreliable.