RAID + EVMS Assistance Please

Ok, here’s the situation. I’ve got a big-ass file server that currently is running 3x80G in RAID5 and 2x120G in RAID1. Lately I’ve been moving files around, symlinking between the /shared partion, the /mp3 partition and so on. Not fun, and a bit of (no, make that a lot of) a pain in the ass. So I thought to myself, what’s a good way to fix this? The answer that came to me was EVMS.

“EVMS provides a single, unified system for handling all of your storage management tasks. EVMS recognizes all of the disks on your system and allows for a variety of partitioning schemes. Software-RAID and logical volume groups can be managed in EVMS. Filesystems can be created and checked, and are automatically updated when changes are made to the underlying volumes. With EVMS, there is no longer a need for several individual utilities for performing each of these tasks.”

This, as I understand it, and from other articles I’ve read will let me create filesystems that can be resized and sit on top of whatever happens be be there, be it RAID, stand alone drives, etc. This means I could create a virtual partition on top of (spanning?) the RAID1 and RAID5 systems I have and create the partitions in that that could be my /mp3, /shared, etc drives.

Alternatively, would this mean that RAID is irrelevant and I can create some sort of funky raid on top of the Logical Volumes that then get turned into one big ass shared drive? I don’t really want/need to have separate partitions for the file storage, it was just when I got the drives and the order I got them in lent themselves to this setup.

Can anyone point me to a tutorial or a good place to start looking at this? I’ve gone through some of the User Guide and the excellent articles by Daniel Robbins of Gentoo fame, and still don’t really get it. Any other sources of info or tutorials out there that anyone has found? Maybe someone in the LUG can do a presentation on this?

Other questions:

  • Can I do everything in the EVMS tool, including things like creating raid devices, or do I have to create and setup the RAID disks first, and then do things with them in the EVMS tools.
  • Can I bundle the raids together (the 120×2 RAID1 and the 80×3 RAID5) to create a single monster disk? Or does this tool not do that magic?
  • What would the best set up be? My 2 RAID volumes are of different sizes, so this won’t work for 1+0 or 0+1 would it? Advice on disk setup appreciated.
  • Segments? Volumes? Oh my…