site_archiver@lists.apple.com Delivered-To: Darwin-dev@lists.apple.com User-agent: Mutt/1.4.1i On Tue, Sep 14, 2004 at 10:49:52PM -0400, Jack Howarth scratched on the wall:
I know this may not be the most appropriate place to ask this question but I am wondering if any Darwin experts here know the limits of the current RAID-1 support in Panther. In particular, I am interested in creating a RAID-1 mirror using two identical SATA drives in a dual G5. I understand that a single filesystem disk can be non-destructively converted over to a unpaired mirror using the command...
diskutil enableRAID mirror disk0
Unfortunately this comamnd fails on a disk0 that contains two HFS+ partitions with an error message that the disk was not appropriate and an error number -9694.
The diskutil man page implies this isn't possible: -------------------------------------------------- enableRAID mirror device Convert single filesystem disk into a unpaired mirror RAID set. Ownership of the affected disks is required. -------------------------------------------------- I think they mean "Convert single-filesystem disk...". In other words, it won't work for disks with more than one filesystem (i.e. partition). I suppose they could mean "Convert one disk with a filesystem", but that seems obvious.
While I can understand that the current diskutil may have limitations on the enableRAID feature I am now wondering if MacOS X 10.3 supports RAID-1 of disks with multiple bootable partitions at all? Can anyone confirm that if I were to destructively repartition the drives and manually create the RAID-1 in DiskUtility (before reinstalling Panther) that I could in fact have both HFS+ partitions on a disk0 set up to mirror with RAID-1 on a second disk? I am a tad worried that I may have run into a nasty limitation of the OS's RAID support.
I'm guessing that is true. When you create a RAID set, you need to give a filesystem type. Filesystems are associated with volumes (i.e. partitions), not raw disks. So I'm fairly sure that a set of mirrored disks is treated like a volume/partition, and not a raw disk. That means you can't partition a RAID set. This isn't that unusual for basic logical volume managers like the software RAID system. I realize hardware RAIDs can do more advanced things, but this is not a surprising limitation, even if it is a bit frustrating for you. -j, who's only mirrored whole disks. -- Jay A. Kreibich | Comm. Technologies, R&D jak@uiuc.edu | Campus IT & Edu. Svcs. <http://www.uiuc.edu/~jak> | University of Illinois at U/C _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.appl... This email sent to site_archiver@lists.apple.com