Software Raid with SATA Disks

[Eóin]

Hello all, happy holidays

I got this notion in my head recently that I should really start doing a better job of backing up my files. What I would consider to be my critical data- thesis files, programming works and other misc. hoby stuff is all very well backed-up. But less critical things like my music and movie collections are too big, I'm running out of room as it is.

So that's the back story. I have a spare pc acting as a file server most of the time sometimes as a workstation which currently runs XP x64. It's got plenty of room for some more harddisks so I was considering a raid 5 setup with 3 new harddisks. But I'm completely clueless when it comes to RAID setups.

Would any experts here know if what I'm thinking is feasible and is there additional software I'd need to install? Thanks all and merry chirstmas again.

[f0dder]

Don't do RAID-5, stick with RAID-MIRROR... with a parity (RAID-5) setup, you can still only afford losing a single disk, and the rebuild operation when that disk fails is intensive, making it likely for a second disk to fail during the rebuild. With mirroring, the rebuild operation is a bit less intensive (although you still have to read the entire of the other disk, for a 2-disk mirror).

The Pro editions of windows support software natively, and you might as well stick with that rather than buying a cheap RAID card. If you want to buy a RAID card, you'd have to go for one of those 3ware/whatever with onboard RAM and battery-backup to get any real advantage over full software raid.

The entry-level promise cards (as well as onboard raid on motherboards) don't usually offer any advantage, and at most an XOR engine to relieve the CPU a bit (and in some cases those XOR engines are so slow they end up impairing disk speed).

[Cuffy]

Just da facts, mon!

http://search.techrepublic.com.com/index.php?q=Raid+explained&t=11

edit by jgpaiva:fixed tinyurl link with the actual link

[Eóin]

Thanks for the replies and Cuffy that's an excellent link.

f0dder when you say mirroring with parity are you suggesting something like :-

RAID 4 (Independent data disks with shared parity blocks)

• Max capacity: (Number of disks minus 1) x capacity of each disk
• Description: A file is broken down into blocks and each block is written across multiple disks, but not necessarily evenly. Like RAID 3, RAID 4 uses a separate physical disk to handle parity. Excellent choice for environments in which read rate is critical for heavy transaction volume.
• Drives required (minimum): 3
• Pros: Very good read rate. Tolerates the loss of a single drive.
• Cons: Write performance is poor. Block read performance is okay.

[f0dder]

Thanks for the replies and Cuffy that's an excellent link.

f0dder when you say mirroring with parity are you suggesting something like :-

Nonono, not mirroring with parity, I meant regular RAID-5 (aka parity) mode.

Stick with a mirror, really. You get about same write speed as a single disk, and decent implementations will stripe your reads; nForce4 lameness won't, linux won't (at least by default), intel RAID matrix <3 will - haven't ever used windows raid, so dunno if it does. And no, read striping isn't dangerous, you still catch errors through drive CRC failures...

A mirror also has the advantage you can always pull out the disk and use it in single-disk mode, you can port it to another RAID controller, etc...