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HP ACU recovery and reconfiguration

 
Jim Mulgrew
Advisor

HP ACU recovery and reconfiguration

Hi all -

Okay, now I've got something I've never seen before. (grin) We have a new server in California where the admin on site was reporting a bad drive. I jumped on the box and started looking around and found something really weird. The server (ML370) was supposed to be set up as a RAID1 on the 1st two drives for the OS and the rest of the drives were to be set up as RAID5 with a spare. Now, I have no idea what happened or how it got this way, but if you look at the attachment, Port 2 SCSI ID 0 thinks its mirrored pair is with a drive on Port 1 SCSI ID 1 which had been the tape unit. (Never seen this before) On top of that SCSI ID drives 1-4 make up the RAID 5 array and SCSI ID 5 is the hot spare for Array B.

The challenge here is to get ARRAY A reconfigured to get the tape unit out and back to some sort of mirror, maybe using the online spare in some way. Because ARRAY A is currently broken, it won't let me make any changes to it. If I delete ARRAY A, I hose the OS and I'm down. Does anyone have any tricks or suggestions on how to beat this? Thanks.
6 REPLIES

Re: HP ACU recovery and reconfiguration

Hi,

This looks weired definietly.

But my freind you have mentioned there is a tape attached to the port 1 of the controller. What is this tape make and model. Because 642 is supposed to take only hotplug internal DAT tapes according to the Product Quick Specs.



By the way you have a solution.

As always have a full backup.

Using the ACU

1. Remove the spare from the Array B.

2. Save the changes.

3. Pullout the spare drive (Hotplug)

4. Reinsert it and the Array A will identify this as a new drive introduced for rebuilding.

5. Check the rebuilding status.

Keep me noted. Send me the array controller firmware revision, I have a one in had and I will try to simulate the problem if I get time and an external DAT tape.

Regards,

Varuna.

Re: HP ACU recovery and reconfiguration

Jim,

I saw something very similar recently and the answer wasn't too difficult although we never got to the bottom of why ACU painted this picture.

Shut the server down and power it off properly for 10-15 seconds to perform a cold boot. This will initialise the SCSI and Raid controllers cleanly. You may then see a message at POST relating to a drive which has failed. Choose to reconstruct it and see if the old(suspect)drive rebuilds OK in this way. If it does not rebuild and the disk is genuinely faulty (amber led), you may find that the ACU has sorted itself out and you can actually replace the drive as expected (i.e. it's reporting things as it should).

It worked for me.

I hope this helps,

Brian
Jim Mulgrew
Advisor

Re: HP ACU recovery and reconfiguration

Hi Varuna -

I had the admin on site disconnect the tape unit from the 642 controller and reconnect it to the onboard SCSI controller. I rebooted the server at that time and the server now sees the tape unit on the integrated controller but the 642 still seems to think there's supposed to be a "drive" on port 1 scsi ID 1. Weird.

- Jim

Re: HP ACU recovery and reconfiguration

In the first place, we should try to build the mirror. Therefor as I said remove the spare from the Array B and save the changes.

Then reinsert it and asign it as the second drive to the failed mirror

For details please refer to my first reply.

Once you have a mirror established, then do any thing with the first hard drive.

Cold boot the server.

Remove and reinsert the Drive on port one.

By the time I will lokk for any advisories related to 642.

Regards,

Varuna.
Jim Mulgrew
Advisor

Re: HP ACU recovery and reconfiguration

Hi Varuna -

Sorry if I have confused things here. I did print off your instructions and gave it a try by removing the spare from Array B and saving the configuration, then removing the spare drive physically from the box. I then reinserted the drive and brought up the ACU. It does see the drive as an unassigned drive but still doesn't let me use it on Array A because it is still in an error state so I cannot make modifications to it. Array A thinks that drive Port 2 SCSI ID 0 and the device on Port 1 SCSI ID 1, are a mirrored pair. How it thinks that, I don't know. We identified the device on Port 1 SCSI ID 1 as originally the tape unit that had been plugged in initially. Wierd, how could we have ever gotten the array to think that it was a mirror.

- Jim

Re: HP ACU recovery and reconfiguration

Hi,

It is too bad. Currently I have no other clue plus I do not have a prpoer cable to connect my 642 to the DLT. Otherwise I would be glad to simulate this.

I think we need help from whom designed the electronics of this controller.

But I will not giveup will continue to lokk for a solution.

It is Saturday and Sunday coming. I will get back on Monday.

Regards,

Varuna.