Expanding RAID5 to larger discs

kaltag · Posted: Sun Dec 11, 2005 4:01 am Post subject: Expanding RAID5 to larger discs

Good evening, I'v currently got a RAID 5 of 6x400GB drives running fine on IDE using mdadm and the kernel RAID 5 driver. I will soon be upgrading to 500GB SATA drives and I'm curious what the easiest/safest way to do this is. Would I just unlug the first IDE drive, plug the SATA drive in, partition it, then add it to the array and let it rebuild then repeat for each drive until all the 500GB drives are installed and then expand the filesystem? Or is there a better way of doing this? Recommendations for tools to do this? The number of drives will stay at 6, only the capacity will increase. I'm using Reiser 3 on the current RAID array if it matters. Thank you.
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NotQuiteSane · Posted: Sun Dec 11, 2005 6:56 am Post subject:

well, I'm not a fan of software raid, but since you don't need more hardware to run it, why not create a new array, then migrate all your data to it, then remove the ide based array?

as to mixing drives, as I understand your 500gb drives would be seen as 400gb if you did that. remember the raid 5 formula is (N-1) * capacity of smallest drive, where N = # of block devices, so you need all drives to match.

NQS
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kaltag · Posted: Sun Dec 11, 2005 6:43 pm Post subject:

Aside from having to hook 12 hard drives for that to work I don't have any real problems with it except that I don't have the $ to buy all 6 500GB drives at one time. I was thinking more along the lines of 1 drive every 2 weeks. I understand that each 500GB drive would be using 400GB until they were all replaced and THEN I was thinking of using the grow funtion under mdadm to add the extra 100GB on each drive then resize the filesystem.
_________________
Yeah, I know about the recovery console. Usually, it doesn't do anything more than I can do with a match, a weedwhacker, and a sledgehammer. Actually, it does a whole lot less. - Caffinehog