Arch Linux

lost eden

Member

Registered: 2008-01-01

Posts: 62

RAID5 advice (PATA + SATA2, probably mdadm)

My Arch box has a 320GB PATA hard disk which is about 98% full & I need to expand. What I plan to do is buy 2x 320GB SATA2 hard disks & using them in conjunction with the current 320GB PATA disk build a software RAID5. Am I going to run into any problems with this plan (e.g. mix of PATA/SATA2, but AFAIK mdadm just sees devices not technologies) or should it all go smoothly?

Arch is installed on a 160GB SATA2 hard disk which will remain untouched. I have a 320GB external drive & I propose to copy everything from the PATA disk to the external drive, then wipe the PATA disk & create the array from empty disks, rather than trying to build the array from a pre-existing data set (which I presume is far more complicated thatn starting from scratch with 3x empty disks). Once created I can copy everything from the external drive back onto the array.

Last edited by lost eden (2008-06-12 14:30:29)

meqif

Member

From: Portugal

Registered: 2006-12-16

Posts: 60

Website

Re: RAID5 advice (PATA + SATA2, probably mdadm)

I had a similar setup (two PATA disks and two SATA disks, to be precise) and had no problems with it.

I think you could create a RAID5 array with the two new hard disks and a "missing" hard drive (which you'd replace with your PATA disk after copying its contents to the new, "degraded" array). You'd create the array like this:

mdadm -C /dev/md0 -l 5 -n 3 missing /dev/new-drive1 /dev/new-drive2

Then, after copying everything from the old drive, just issue

mdadm /dev/md0 -a /dev/old-drive

This way, you'd save some time (you'd copy your stuff only once).

Last edited by meqif (2008-06-13 22:16:59)

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