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Data corruption in RAID 5

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March 8, 2007 5:44:29 PM

I've got a problem at work. We have a Dell powervault 220S with 6 drives in it they are in a RAID 5 array. early this week we had it start giving warnings in the Dell array manager. these warnings became more frequent and i started getting ntfs errors for specific folders. I had the drive replaced and i've rebuilt the array (succesfully) but 1 of the 2 folders that were being detected by the operating system is still showing as corrupted and is denying access to it. I can't even delete the folder.
I have backups but i really don't want to have to rebuilt the entire volume.
the OS (Windows server 2003 R2) wants to run chkdsk. I don't want that as chkdsk isn't raid aware.

Any ideas or suggestions?

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March 8, 2007 6:09:48 PM

Quote:
I have backups but i really don't want to have to rebuilt the entire volume. the OS (Windows server 2003 R2) wants to run chkdsk. I don't want that as chkdsk isn't raid aware.


Chkdsk checks the file system, it has nothing to do with the physical architecture of the volume. It doesn't matter whether the volume is on a single physical disk or a RAID array, chkdsk doesn't know and doesn't care.

Since you were getting NTFS errors on the volume (probably due to some very minor corruption related to the bad drive in the array), chkdsk will probably be able to fix it.

Run "chkdsk x: /v" (where x: is the drive letter of the array). This will run chkdsk in read-only mode with verbose logging, where it won't make any modifications to the disk and will tell you about all errors that it finds in the file system.

If it's just a few errors, it's likely chkdsk can fix them. Run "chkdsk x: /f /v" to fix the errors. Depending on whether chkdsk can get exclusive access to the volume, it may want to actually run it on the next reboot.

If there's a lot of file system corruption, you may want to restore from backup anyway (at least the particular folder that's involved) because there's no guarantee chkdsk can fix everything. It can make the file system free of errors, but that's no promise that the files themselves are intact.
March 8, 2007 6:37:41 PM

thanks, the folder size is insiginficant. i already made a copy from backups. i had heard that chkdsk could damage a raid 5, as it turns out it seems that it only damages a raid 5 if the array is degraded at the time.
thanks for the response.
edit for spelling
March 8, 2007 9:03:49 PM

This is fun, it when from only listing a couple of errors to listing Event ID 55 and 26 about 9 times a second continuously. the OS is still saying that the same folder is to blame. any ideas why it would start reporting errors more rapidly all of a sudden?
EDIT-
I'm still receiving no errors from the array manager and there are no smart error being reported.
!