RAID 10...went bad and now rebuilding...how do I know what went wrong?

Posted on 2004-10-25
Medium Priority
Last Modified: 2011-10-03
I have a computer with 4 hard drives in a RAID 10 configuration.  2 hard drives are striping and 2 are mirroring.  

I came in today and the computer was making a constant beep sound, so I rebooted and got some message that the RAID was corrupt or something, but before I could write the message down the RAID started to rebuild itself.

I have a lot of very important data on this computer, and a program was running creating files when this happened, and I am concerned about both the integrity of those files as well as the situation of my 4 hard drives.  The computer seems to be fine now.  The RAID is still rebuilding itself.

My questions:
1) How can I find out what happened?  Is there a RAID log or something?  I cannot find any RAID utility software in the computer.
2) How can I see that status of the drives?  I went to Disk Management but it just shows one disk that is the size of the 2 striped HD's combined.  I don't know if one of the hard drives has gone bad, and I can't find anywhere (like Disk Management or Device Manager) that actually lists all 4 hard drives.

FYI I am new to this RAID stuff so please be kind on terminology!  A longer, rambling answer is preferred to a short one, as I have a lot to learn about managing this computer!

Question by:markabe1

Expert Comment

ID: 12408018
hi, markabe1

What kinda system is it HP, Dell, or else....
What Raid card is in the system built in Raid controller or a controller card Adaptec ??....
LVL 15

Expert Comment

ID: 12408883
It is a natural thing for you to see a single sized hard drive on the 'Disk Manager' for the reason that 'Striping' is actually the combination of two drives thus creating a single hugh capacity along with high transfer rate.

Large data chunks are seperated to a 64KB sized packets (the size may vary) and forwarded by the RAID controller equally into the two drives that are set as striped. That means that part 1 goes to drive 1, part 2 goes to drive 2, part 3 goes to drive 1, part 4 goes to drive 2 and forth... This means that part of a file is located in drive 1 and the other is located on drive 2. This leads us to the conclusion that the system HAS to see the drive as a single unit.
As for the mirroring; Sience this method is fast, it is not reliable and this is why manufacturers desided to combine the mirrorring archiecture to the striping technology thus creating a more reliable technology.

Where does this lives us?
Can you see data on the 'Single' drive? If your data is available, there is a way to see which drive fails out of the four and replace it with a properly functional drive:
You can use the 'diskpart' utility came with Windows XP by default or being added to the Resource Kit in Windows 2000:
1. Enter command prompt (Start => Run... => type 'cmd' => type 'diskpart' and press 'Enter' => and press 'Enter').
2. Type 'list disk' to view the complete drive's list on your computer.
3. You CAN select a drive to diagnose by committing the following commands:
   3.1. Type 'select disk <drive number>'.
   3.2. Type 'detail disk' to view the drive's status...

If you dont see the data it is a reasonable that the RAID controller just rebuilt the RAID from skrach thus in this normal usage, you wont be able to view data. To get arround that, you may need to initiate a recover procedures. In order for us to be able answer that question fully, we will need a few answers:
1. What model is the controller (as cooledit suggested)?
2. When you see the drive in 'Disk Manager', can you see it in 'My Computer'? (i.e. is that drive is assigned by a drive letter?).

Good luck and dont panic!!! Data is harder to loose, harder than you may think...


Author Comment

ID: 12413726
My system is an HP Workstation xw8200 with Windows XP Professional.

Details on the array are below, but my remaining questions are:
Can I still run the computer?  Is it simply not mirroring, and I can ignore that for a day or two, or am I at risk of file integrity?
I am assuming that either one of the hard drives is failing or the array controller is failing.  Is this accurate?

Specific details on what is happening will be greatly appreciated!

I rebuilt the array last night and everything seemed fine.  I ran the computer last night and this morning I came in and it was doing what I believe is a warning beep/squeal.  I went into the array configuration utility and here are the messages I got:

Following arrays have missing or rebuilding or failed members and are degraded:  
Array #0 RAID-0
Array #63 RAID-1

In Array Properties main screen:
Adaptec 2120S Family Controller
#0 Array Configuration Utility

Array Properties:
Array # 00: RAID 0   Type: RAID 10
Array Size: 136.7 Gb   Stripe Size: 64Kb
Array Status: Rebuild 4%

Array Members:
63 RAID 0   RAID 1 68.3Gb
62 RAID 0   RAID 1 68.3Gb

If I then click on each array member (63 and 62) I get more array properties:

Array Properties:
Array #63: RAID 0  Type: RAID 1
Array Size: 68.3 Gb
Array Status: Rebuild 5%

Array Members:
0:00:0 Seagate ST373453LW 68.3Gb
0:02:0 Seagate ST373453LW 68.3Gb

Array Properties:
Array #62: RAID 0  Type: RAID 1
Array Size: 68.3 Gb
Array Status: Optimal

Array Members:
0:01:0 Seagate ST373453LW 68.3Gb
0:03:0 Seagate ST373453LW 68.3Gb

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Author Comment

ID: 12514700
I replaced the RAID card and everything is fixed now.

Author Comment

ID: 12514711
Please close this question.  There was no followup and I ultimately solved it myself, so I don't feel anyone deserves the 500 points.

Accepted Solution

modulo earned 0 total points
ID: 12772070
PAQed with points refunded (500)

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