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Raid 5 Problem

By stack.bob1 ·
Hi - I have a 3 drive Raid 5 Array all Seagate drives (relatively new). The first one is a 1Gb the other two are 750Gb.Been working great for a while. I also have a 750Gb spare (Seagate) in the array set. I noticed last night the drive was rebuilding. Not clear if it had brought in the spare or just rebuilding from the original 3 in the set. I let it go overnight. Today I found a blue screen. I rebooted and the OS wouldn't load. When I got into Cntr I found the first two drives in the array set "offline" and the 3rd and 4th (must be the spare) both as "Member Disk (0)". I can't boot and I'm not sure how to resolve this situation. Can you help please? I really need this data....

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Whoops.

by cmiller5400 In reply to Raid 5 Problem

Sounds like one of the 3 drives in the array puked, then started to rebuild to the spare and then a second drive in the array bought the farm. I'd contact the manufacturer of the raid card (since you didn't mention what it was). RAID failures tend to get VERY nasty, VERY quick.

Oh, do you have backups? If you don't and you really need the data, there is some software that MAY be able to recover some of the data depending on how the drive failed. If you can't even get the drive to show up, plan on spending 5-6 figures for a data recovery warehouse to attempt to do a recovery; and to boot, it may not be successful. And remember the more you play with the drive the less of a chance there is to recover data.

ALWAYS backup data, even if it is on RAID array. RAID arrays don't protect you from corruption. And RAID arrays are just as vulnerable as a single non RAID disk.

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If that's true

by tintoman In reply to Whoops.

And it does seem that it might be, then the failed drive needs to be removed and the "rebuilt" one needs to be inserted in the same position that was occupied by the failed one.
Worth a try I would have thought

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BUT...

by cmiller5400 In reply to If that's true

If the second drive that failed, failed during the rebuild, you are screwed. Bye-Bye data.

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Yep, the array can survive with 1 failed drive

by CG IT In reply to BUT...

and rebuild itself with the spare after the spare is put into the RAID array. But a RAID array can not survive 2 failed drives because the parity bits needed for the rebuild are not there.

Here is an article about common mistakes in rebuild of RAID 5 arrays. The most common seems to point to your dilemma. Your RAID 5 array that is 3 disks not 4 but you think it's 4 disk because of the hot spare. Hot spares may not part of the RAID array and if you rebuild a 3 disk but specify 4 disk array, you lose data.

http://www.quetek.com/RAID_mistakes.htm

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Well for starters here you need Seatools for DOS

by OH Smeg In reply to Raid 5 Problem

You can get that here

http://download.seagate.com/seatools/registration.nsf/eula/desktop

Download it make a Bootable CD by following the directions for use and boot off that Disc to test the individual drives.

If they all work properly here you may need to disconnect them from the RAID Controller and test in a different system the RAID Controller has failed and that's just as nasty as 2 Drives Failing close to each other.

But none the less you need to know what you are attempting to work with before proceeding any further.

Col

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