Adding a drive to a RAID setup
I've got a box cobbled together to run as my NAS.
1GB ECC Memory
ATI x1300pro video card
3x 640GB AAKS WD hard drives in RAID5 (SATA drives)
1x 15GB drive for OS (IDE drive; OS is Gentoo using md for RAID management)
But it's getting pretty full. (only have 150GB free space). The drives are $70 on ZipZoom and $75 on NewEgg.
Here's the question. I'm sure that sometime after adding a 4th drive to the array (md lets you just add a drive to expand the array) I'll want more space, and at that time, the only answer will be to use larger drives, replacing all 4.
Would I be better off getting a 640GB drive now, or installing something larger so that I only need to upgrade 3 drives down the road?
A third option, I guess, would be to add a controller/RAID card so that I can go past 4 drives in the array.