Recovery of an Apple RAID partition

Dachnaz

Hi all,

I was hoping to get some help with setting up a RAID configuration. I have two drives that were configured in a RAID1 setup in an Apple Xserve. I've installed Gentoo on the machine and am hoping to correctly configure the drives for use in a RAID array again. The drives each have three partitions, with the second partition being HFS+ and being 999GB in size. To date I have used mdadm to create the array using these two mirrored partitions. When trying to mount /dev/md0, however, no filesystem can be found. Trying to mount the partitions individually has the same effect.

Dachnaz · Posted: Mon Nov 18, 2013 8:31 pm Post subject:

As an update, I used testdisk to fix the HFS+ filesystems. The process was a little convoluted so I want to share with others what I did.

I stopped the RAID array. I ran testdisk and chose the individual hard drives. Then, I selected EFI/GPT table type. I selected Analyse, performed a quick search, and went back to the menu to chose Advanced (right beneath Analyse). I selected the partition of interest and changed the type, choosing Mac Raid and then HFS+. This opened up the Superblock option when viewing the partition table. I selected Superblock and then merged the volume header and backup volume header with the second option on the menu (which does not appear anymore, now that it's fixed).

However, when these partitions are assembled in a RAID array, they become unmountable. I'm guessing I need to write a partition table for the RAID device itself?

NeddySeagoon · Posted: Mon Nov 18, 2013 10:05 pm Post subject:

Dachnaz,

The Apple Xserve uses a hardware raid system

The kernel supports the raid card. Without the raid card, you need to reverse engineer the data layout on the drives. That will be non trivial for any raid level except raid1.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Dachnaz · Posted: Tue Nov 19, 2013 8:20 pm Post subject:

Thanks NeddySeagoon.

Since the hard drives have always appeared as two separate block devices, I think the optional RAID card was not installed in this unit. lspci shows no RAID controllers, just the SATA, IDE, and SCSI (LSI Logic SAS1064, which looks like it could control something important...). Other users indicate that LSPCI shows up something like "01:00.0 RAID bus controller: Apple Computer Inc. Device 008a (rev c

" for the Xserve RAID card. Software it is. I've just copied the contents of one of the drives to a third, and will reconstruct them from scratch using a saner filesystem than HFS+.

NeddySeagoon · Posted: Tue Nov 19, 2013 9:11 pm Post subject:

Dachnaz,

Dachnaz · Posted: Wed Nov 20, 2013 8:01 pm Post subject:

I understand the LSI Logic chipset is the controller for the devices, but it is not a hardware RAID controller. If the system used hardware RAID, the volumes would not appear as separate block devices. Is this not the case?

NeddySeagoon · Posted: Wed Nov 20, 2013 10:35 pm Post subject:

Dachnaz,

Thats probably true.
I don't know if the LSI Logic card has a JBOD mode
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.