RAID5 for Linux

[bob at rsi.com (Bob Gorman)]

At 10:16 PM 4/28/2004, Bob Keyes wrote:
>Well I am going to try out a software raid first, but use a second IDE PCI
>controller to have 4 channels, one per drive. If the performance isn't
>good enough, then I'll move up to hardware raid. I figure I'll get four
>160GB drives, as they are the cheapest per byte.
>
>Then, I'll try to decide if I should try to boot from the raid, or have a
>simple 10gb or whatever drive to boot the OS from, and the raid just for
>data. Hrm....that means another controller.

You can't boot from OS RAID-5, only RAID-1, at least under RH Linux.

My personal preference is to have a cheap pair of small disks in RAID-1 for OS. Then put data on a separate group of better disks in RAID-5.  The RAID-1 disks on the controller built into the motherboard using OS RAID. The RAID-5 disks on a separate controller, hardware or OS RAID-5 depending.

Also, as Rich points out you could do all this on 3-disks under OS RAID by mixing partitions. eg:

disk0: 10gb for RAID-1, 150gb for RAID-5
disk1: 10gb for RAID-1, 150gb for RAID-5
disk2: 150gb for RAID-5

I'm sure you'll find something to do with the left over 10gb. Perhaps go dual-boot or use it for anonymous ftp storage.