Help with broken raid5?

[Steve Noel]

Hi all,

 

I'm hoping to get some help with a raid5 container that went belly-up on me.  Keep in mind I'm relatively noob with Linux.

 

Last year I bought an 8 TB NAS box (iomega ix4-200d) which came as a raid 5 standalone unit, running a Debian Linux OS.

 

Last week it declared drive 4 was in an error state so I replaced the drive and waited for it to rebuild.  Overnight I got 3 emails from the unit stating:

 

1)      That a "recoverable error" occurred on drive 1

2)      That the raid rebuild had completed

3)      That the StorCenter device had failed and some data loss may have occurred. Multiple drives may have either failed or been removed from your storage system. 

 

Of course, none of the drives had been removed.  And I don't have confidence that the drive 4 rebuild completed successfully.  Now the until declares that all 4 drives have been replaced and wants permission to format them.

 

Luckily, the unit has SSH enabled and I can log in to the CLI.  But this is where I need some help.  I want to force the array to come back online to see what I can salvage from it.  The vendor's only suggestion was to send the drives in and for $4000-$5000 they would attempt data recovery for me.

 

I've been reading up on MDADM and have some info on the state of the container...

 

root at NAS2:/# mdadm --detail /dev/md1

/dev/md1:

        Version : 01.00

  Creation Time : Thu Mar 25 19:28:35 2010

     Raid Level : raid5

  Used Dev Size : 1951474176 (1861.07 GiB 1998.31 GB)

   Raid Devices : 4

  Total Devices : 4

Preferred Minor : 1

    Persistence : Superblock is persistent

 

    Update Time : Tue Oct 25 02:24:28 2011

          State : active, degraded, Not Started

Active Devices : 2

Working Devices : 4

Failed Devices : 0

  Spare Devices : 2

 

         Layout : left-symmetric

     Chunk Size : 64K

 

           Name : storage:1

           UUID : 53758a21:e972eb25:0c4ddf95:f4dd42b8

         Events : 212414

 

    Number   Major   Minor   RaidDevice State

       0       0        0        0      removed

       1       8       18        1      active sync   /dev/sdb2

       2       8       34        2      active sync   /dev/sdc2

       3       0        0        3      removed

 

       0       8        2        -      spare   /dev/sda2

       4       8       50        -      spare   /dev/sdd2

 

Can anyone offer guidance on how to safely force these drives back online?  I'm thinking that if I can get drive 1 back online the array should come back alive and I can copy data off of it.  Even if drive 4 never completed rebuilding the data should be there.

 

Thanks in advance,

Steve

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