RAID 5 Rebuild

By manojjjacob ·
I have a RAID 5 server with a failed hard disk. I'm not much into these kind of things but at present I have to perform the replacement / rebuild and I'm not so sure how. Can someone tell me the procedure. Can I shut down the server and insert the new disk? Can i just open the web bios and rebuild manually? Any other precautions to be taken? There are no problems with keeping the server offline for some time.

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You need to provide more information here

by OH Smeg Moderator In reply to RAID 5 Rebuild

Because the different systems have different ways to Repair/Rebuild the Arrays.

If in doubt RTFM which may sound trite but is really the best way out of the current problem.

If you are unable to get a copy of the manual just post back with the Make/Model of the Server or M'Board Make & Model and someone here will be able to help you with a solution.


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In most cases...

by scott_heath In reply to RAID 5 Rebuild

You should just be able to remove the failed disk and replace it with a new disk of identical type. The system will rebuild the disk on the fly. You will notice some degradation in server performance during the rebuild.

I can only pray that these are hot-swap SCSI and not SATA. SATA takes longer and kills server perfomance during rebuilds.

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RAID 5 Rebuild - Acer Altos

by manojjjacob In reply to In most cases...

Thanks for the replies.
The server is an Acer Altos G700 Series (Model G701) running on Windows 2003 Server with 3 hard disks (Seagate ultra 320 SCSI; Model no. ST373307LC). AS I mentioned earlier, I have no problems in keeping the server offline for a day. If it's a better idea to keep it offline, it can be done.
Are there any chances of losing data in case the new hard disk is not accepted or something?
How can I know the status, like whether rebuilding is happening, if I just do a hot swap?
I have restarted the server a few times with just 2 hard disks in (after removing the bad disk). Will this by any chance cause the automatic rebuilding to fail?

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by scott_heath In reply to RAID 5 Rebuild - Acer Alt ...

I see you have the option of 2 different LSI RAID controllers direct from Acer. Did you buy one of these or did you purchase one seperately and install it your self? The tools you have at your disposal for monitoring will depend on the RAID card more so than anything else. Here's to hoping you aren't using Windows software-based RAID.

It's not "better" or "worse" to keep it offline. I depends on how you want to se things up. The scenario I described leaves little room for disaster, but leaves you having to move data to the new volume.

Imaging is most likely safe, but what happens if the image is corrupt and you didn't know it and you blew away your RAID config which wipes the drives? I am assuming you make good backups so hopefully the worst case scenario is that you would have to rebuild using the CD and then restore data and configs. I would suggest you back all these things up prior to starting this process regardless of the path you choose.

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by manojjjacob In reply to Well..

Well, I really don't have much idea about the RAID controller. It wasn't installed by me and I'm not a system administrator. I just am in the awkward position of having to handle the situation right now. I do have backups on tapes as well as external hard drive. What did you mean by rebuild using the CD? Do you need any information that would be helpful at the moment? Are there any chances that the server crashes on inserting the new disk, if the RAID has got issues?

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The Acer Altos isn't much help as that is a long running model

by OH Smeg Moderator In reply to Well....

There have been Altos since the P3 days and there are currently several models with different Hardware configuration available now.

Having said that the RAID should rebuild when you insert a new drive.

As for what is meant by rebuilding with the CD that means reinstalling the complete OS and setting up the machine again. As for the unit crashing yes it's possible but unlikely unless there is something else happening that hasn't been mentioned. As there are different Hardware available the model of the Server would be of help but I'm assuming that it's setup correctly and you just need to replace the faulty drive which needs to be at least as big as the one removed or bigger. If you use a smaller drive that could cause problems though if the RAID is properly setup it should refuse to accept the smaller drive.

No matter what happens it is always advisable to have a current Backup available before starting anything as while things should work smoothly if you do not have a fall back procedure in place things will go wrong when you can least afford them to happen.


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