RAID 5 - 1 port on backplane dead, drives are fine

[oynaz]

Hi guys,

I need to pull some virtual machines off a Dell PowerEdge server with issues.

I have 3 disks in a RAID 5. AFAIK, the disks are fine, but port 2 (they are named 0,1,2,3) on the backplane is dead.

How do I get data of this bad boy? I cannot get it to boot from the RAID array, as it goes in a failed state. Moving the disk to port 3 does not help. It find the disk, but port 3 is not part of the array.

Any ideas?

 

[ch33zw1z]

You have a RAID 5, pull the disk out of slot 2, and boot up off the remaining 2 disks. The array will be degraded, the controller will do parity calculations the whole time, but this shouldn't be an issue.

I've had to do this before to get servers back up. Either the disk drive is causing so much noise on the bus that the array fails, or the slot on the backplane is causing it. I recently had a RAID 1 setup that needed troubleshooting, it was a failed drive causing the entire array to fail during POST.

If this doesn't work. Put the drive back in slot 2 and enter the Dell PERC configuration utility when the server boots up and view the array. Keep track of which drive is which if you start pulling them out.

 

[oynaz]

Thanks for the tip.

The RAID has entered a failed state, and I cannot figure out how to clear this without all 3 disks. I can enter the RAID configuration utility, but I do not see any way to clear the failed state in here. Any tips?

 

[ch33zw1z]

What is the status of hte drives? I have very limited experience with Dell's. Look for options to activate the array. Or options to set the drives online manually.

 

[rsutoratosu]

Do you have another server that you can put these disk in. I had a backplane failure with my old 2850 and it took ALL the drives with it. You should also call dell, still have support ?

What model server and perc card ? 5/6/7/?

 

[oynaz]

Argh, the guy whoh set it up mistook RAID 0 for RAID 5 :-(

So, I have three healthy RAID 0 drives and a faulty backplane.

The server is a model T605, and I am one screwed IT guy.

 

[ch33zw1z]

Do you have another server to put the drives into? RAID configs are stored on both teh controller and the drives.

If you have another server:
1. boot it up with no drives installed, restore defaults to the RAID controller.
2. Installed the drives
3. Enter the controller setup on bootup, copy the config FROM the drives TO the controller.

Alternately, if you have a spare server with the same backplane, then uninstall it from that server and install it in the server with the failed backplane.

You're not screwed all the way yet!

 

[Kremlar]

Depending on the RAID controller you could probably get a breakout cable that goes direct from the controller to each drive, bypassing the backplane.

But what makes you think you have a bad port on the backplane and not a bad drive? While a bad port on the backplane can happen, a failed drive is far more likely.

 

[oynaz]

I have tried moving the drive from port 2 to port 3. The drive is not detected on port 2, but it is on port 3. I have only tried switching drives (keeping track of which is which), same result.

So I have to conclude it is the backplane.

But I can see I need some additional hardware. Might be cheapest to get someone external to do this.

 

[Emulex]

why don't you just get a fan out cable and plug the drives and raid into another pc?

raid controllers store the raid data on each drive (even other raid sets) and then also store the WWN on the raid card and on the drives. so you can mix up! only crappy consumer sata drives had no WWN - but all drives have WWN these days, including modern SSD.

fan-out cables work in a pinch

perc's will work in another PC if you google SMBUS/SMBIOS tape trick