Should I include my OS partition on my RAID or separate hard drive?

Question

I plan to build a Linux (Ubuntu 10.04) home file server soon with 3-5 x 2TB hard drives in RAID 5 software raid but I'm not experienced with setting up RAIDs.

Should I include the actual Linux host in that RAID setup or should I use a separate drive (I'll have an SSD lying around soon) and what are the caveats to this?

If and when I need to reinstall the host OS, will it be able to use the the old raid cluster?

Answer 1

The OS should not be in the RAID configuration at all. Here's what you can do:

Option 1

Install your OS on a smaller partition of one of the drives, and partition the rest for use in the RAID cluster.

So, assuming you're using 4 disks:

• Disk 1: 50GB for OS, 10GB for Swap, 1900GB for RAID partition
• Disk 2-4: 1900GB partitions each.

Option 2

Keep OS on a separate disk.

So, assuming you're using 5 disks:

• Disk 1: Contains OS. Not included in RAID cluster.
• Disks 2-5: Partition however you want, say 2000GB each. These will make up the RAID cluster.

In either option 1 or 2, you should be able to reinstall the OS without destroying the RAID cluster.