Bad sectors in a RAID 1 array (Matrix RAID)

Wraith44

Limp Gawd
Joined
Oct 9, 2007
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161
Two weeks ago, I purchased 2 of the Western Digital 640GB Black drives from the Egg with the intent of using them in a Matrix RAID array. When I received the drives, I proceeded to configure them with a 275GB RAID 1 partition on the inside track and the remainder in a RAID 0 partition (~595GB) on the outside track.

I benchmarked them and was very pleased with the results, so I copied all of my data over to them. However, I began to notice that every few days, the RAID 1 array was needing to run a data integrity verification (or something similar...I don't recall exactly what it was called), which took about an hour to run. I didn't really think anything of this because sometimes my system locks up (Windows XP...I know, big surprise) and I have to reset it. It's happened a few times when it didn't lock up though, and the only reason I could think of is that it might have to do with hibernation, since I use that frequently. I know that a dirty shutdown will trigger the integrity scan, so I just ignored it.

Cut to this past Sunday evening. I tried to hibernate the PC, as I always do, and I noticed that it was taking a very long time (2+ minutes vs. the normal 20 seconds). When I turned my system on the next day, it came up with an error stating that the RAID 1 array was in a degraded status and that one of the drives was in an "error occurred" status. The RAID 0 array was in a normal status.

I was able to boot into Windows, but it was having some difficulty doing so (freezing, etc). So when I was finally able to get to the desktop, I ran a scan on both the C and D drives (RAID 1 and 0, respectively). The scan found numerous errors on the D drive, which the RAID controller said was fine, and nothing on C, which I expected since the bad mirror was offline. After everything was repaired, I marked the bad mirror as normal and rebuilt the array. After rebooting 9 hours later, the array was once again marked as degraded and with an "error occurred" status. I ran another scan, fixed a couple more minor problems on the D drive, marked the array as normal and rebuilt it yet again.

Cut to this morning and it's still showing up as degraded and an error occurred. Now it seems to me that one of the drives probably has bad sectors on it. However, I'm confused as to why the RAID controller hasn't marked them as bad, so my first question is this. Is there a way to scan for bad sectors in a RAID array, or do I need to break the array and scan it that way? Second, assuming there are bad sectors and I am able to mark them as bad, what's to prevent this from happening again in the future? Shouldn't the RAID controller have done this when it couldn't access the data? Why would it allow me to rebuild the array 2 times over the same bad sectors?

Thanks in advance for any assistance you guys can offer!
 
Obviously one of your drives is going bad. As for the RAID controller "marking the sectors bad" that is more the job of the drive, not the RAID controller.

You need to replace the bad drive, it should be warrantied if you can wait for the shipping.

Just curios why you did a RAID 1 of the C drive and RAID 0 of the D drive? Most people do RAID 0 of the C drive for performance and RAID 1 of the D drive to keep their data safe.
 
I just broke the array and am running a scan now. The Western Dig drive scanner threw up an error right away, so I'm running a complete disk scan now. It looks like I'll have to pursue a warranty replacement, which sucks. I've never had a bad HD from Western Dig in the past, but there's a first time for everything.

As for why I made C a RAID 1 and D a RAID 0, my OS is installed on the C drive, and that's where all of my data is stored, so I wanted the redundancy there. My D drive is games and temporary storage/swap, so that's where I wanted the speed. I know that a lot of people will short-stroke the RAID 0 partition, but I figured the mirrored array could use the speed bump more than the games.
 
Get the drive diagnostics from the Western Digital web site. You will want the Dos version that is run from a CD. You will prolly have to remove the drives from the array to test them.

Run the long or complete test, figure out the bad drive, and replace it. The Egg will be slower, but you will get a new drive. WD will be faster but you will prolly get a refurb.

Don

/edit/ Hmm, seems we were typing at the same time.
 
As you stated, I seems that I have a bad drive, judging from the fact that the Data Lifeguard Diagnostic disk wouldn't even run the full scan because there were too many errors. :D Thanks for the help, guys.

At this point, I think I'll just keep using the working RAID 1 array in a degraded state and rebuild it when I receive the replacement drive.

In the future, would running the diag disk on a new drive before I RAID it be a good idea? I know most drives typically go bad in the first month of use. With that in mind, are most bad drives typically bad right out of the gate, or do they tend to start out ok and then degrade over a few days/weeks?
 
There is no set rule for that. People argue both ways on this question all the time. I personally like to do the full format on a new disk.

Don
 
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