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I'm pretty sure I'm dealing with at stuffed RAID 5 array. Two of the drives were listed as failed in /proc/mdstat and mdadmdetails:

   0     0       8       33        0      active sync   /dev/sdc1
   1     1       0        0        1      faulty removed 
   2     2       0        0        2      faulty removed 
   3     3       8        1        3      active sync   /dev/sda1

md127 : inactive sdd1[0](S) sdb1[3](S) sde1[2](S) sdc1[1](S)
      3907039744 blocks

So sdb and sdd are failed. I then ran SMART diagnosis on my drives and confirmed that I've got current pending sectors, about 1000 of them on both of the failed disks.

Then running badblocks has confirmed that I do have many badblocks about. Trying to zero these out by hand would be a total nightmare, being in RAID5 which I can assemble but can't start anymore and then in LVM makes it a real pain in the ass. I think following something like this just isn't going to work.

I'm open to using MHDD if people have confirmed it to work (suggestions?), it was slow when I was trying it so I aborted and instead started backing up the drives instead.


Currently doing a ddrescue and moving the data over to other disks, hopefully will be able to make a master copy - possibly zero out stuffed drives, and then dd copy back to those drives. Though not knowing much about ddrescue I feel I'm just going to be moving my problem about instead of fixing it.


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To update, I know this is an old one, but I did fix this problem. I used ddrescue to do this http://www.gnu.org/software/ddrescue/manual/ddrescue_manual.html

Basically I had 2 corrupt 1TB drives out of the 4 in my MDAMD RAID 5 array. I had 2 1TB drives lying around that were the same size (or slightly larger), I basically did ddrescue on a broken drive targeting a "good" disk. I then ran chkdsk on the restored "good" disk. I did that for the other drive then added both the new drives back to the array and got my LVM running and tested that they worked. All was fine.

Formatting the corrupt drives with dd then testing them with badblocks, chkdsk and smartmontools throughly I found that there was nothing wrong with them and the corruption was due to a power outage. I then dd'd the "good" drives back to the original drives, added them to the array, tested etc... and put my "good" drives back in storage, they're old and not AV drives like all the others so I didn't want to risk it with them.

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