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alanon
12-21-05, 10:19 PM
I was wondering if anyone knows much abour raid 5.

We have a server at work which had 3 drives in raid 5. One of the drives failed so we took it out and we are waiting on a replacement drive.

The performance was terrible on the server. We did a remote reboot late at night, since no one would be working, and after the reboot we can't get back into the server.

Does anyone know a reason why this server would not come back up. With 2 drives shouldn't it still be functional?

Thanks in advance for any suggestions.

retsam
12-21-05, 10:47 PM
no. the raid set is broken. you need to replace the drive so that the raid parity can be rebuilt. here is a good image of what raid 5 is.

http://public.globaltechpost.com/raid5.gif

without that drive you cannot rebuild the parity set. please dont tell me you change it to raid 0. if you did the data might be lost. once you get the new drive the parity set should auto rebuild depending on the raid card in use.

alanon
12-21-05, 10:50 PM
We ddin't change anything, one guy said we could reboot and everything would be fine because you only 2 out of the 3 drives to be good for raid 5 to work.

So is this server dead until we get a replacement drive in it and rebuild the container?

alanon
12-21-05, 10:58 PM
Could the problem be that the bad drive is not in the server right now?

If the drive was in there would it boot up and just let me know there was a failed drive?

retsam
12-21-05, 11:04 PM
ya know what, the times ive had to rebuild my raids ive always had a disk around. now that i think about it you might have to go into the raid bios todo a rebuild. remotely will not work in this instance. what raid card is this?

Starscream
12-21-05, 11:19 PM
Raid 5 on a 3 drive array is just asking for trouble.

I've seen numerous raid 5 arrays with so little drives go tits up and not rebuild when you replace the dead drive. You need a LOT of drives for raid 5 to really work well.

I'm 99% positive you'll need to have a replacement drive in there and rebuild the array before you can boot that server into windows again. I really hope for your sake it rebuilds properly.

alanon
12-21-05, 11:22 PM
I don't think it was an add-in card, can't say for sure since I didn't build it.

It's a Dell 2850, the problem is its a refurb.

I know the drives are Seagate Cheetah's 74GB SCSI.

To make matters even worse we had a Exabyte 10 tape robotic library hooked up to it which died 3 days ago and we are waiting on a replacement for that as well.

retsam
12-22-05, 06:44 AM
oh boy, its sounds like you need an electrician as well. is this server hooked up to a UPS? i would recommend those to your employer. now that im awake , i know you need that third drive to rebuild the parity..you should also tell your employer they should keep a spare drive around just in case this ever happens again. i know when im consulting and when i first get into a place i always tell them to have a few extra parts around for the server (ill get called in after the fact). they seem to listen after just one event. this would be a great time to spring it on to them. they will listen now.

dandano
12-22-05, 02:22 PM
RAID 5 is *supposed* to work if one drive goes down. You just lose your parity with the lost drive. Admittedly, my experience is with a 6 drive RAID 5, but I think it should be the same fore any RAID 5.

danh

DiscipleDOC
12-22-05, 02:54 PM
I had the very same thing happen to me about a month ago. I had to go into the adaptec bios and rebuild the raid set. After I was done, I then had to reinstall my o/s, apps, etc. It was not much fun, either.

I called Dell gold tech support before I started, and they did not have a clue on what to do.

alanon
12-22-05, 07:54 PM
I wanted to update you guys on what happened, we threw the bad drive back in and the server booted up.

Because there are only 2/3 drives in good shape performance is pretty bad. But it is working. We are waiting to have a new drive shipped from Dell.

Hopefully that will come soon.