software Raid5 Storage

I finally got myself a decent file server setup. 4 disks using software raid5. I took an old (but still pretty powerful) machine I had lying around and added 4 new disks (samsung 400GB) and a sata controller (Promise TX4). Of course I went for a Gentoo installation, as I know that distribution the best, and more importantly, I like it. There is more then enough usable documentation on the software raid part. Now I’m not really a sysadmin so this took me about 2 days to set up.

I partitioned the disk in 2 parts:

Raid 1 100MB for /boot
Raid 5 for the rest /

First I tried with LVM2 but that seemed to fail miserably at boot time, so I dropped that part and just made it a normal ext3 partition. The array seems to be working fine now (no errors as of yet) and it does not require any noticeable cpu power. I am amazed. In my humble opinion there seems to be no need at all to use a hardware controller if you’re just using Linux, besides the fact that a hardware solution provides multi-booting and easy setup. Linux software raid is far more flexible then hardware as it seems to accept any block device (maybe even an iPod?).

Today I disconnected one drive, to see if it still worked. The complete system booted perfectly without the fourth drive. After the reboot with the fourth drive reconnected again, it needed some rebuilding. A long rebuild of almost 6 hours.