RAID Setup

Troy Duran wrote on 8/16/2007, 3:51 PM
Whoever said 'There's no such thing as a stupid question', never met my stepdaughter- or read my posts out loud... Seriously though, at the risk of revealing my ignorance, I'd like to find out before I wipe my drives again- My computer is set up with RAID 0 (I know, but I back it up EVERY day). However, I only have my data drives striped. The OS and programs are on one physical drive and the data on 2 others. Aside fro them benefit of adding another disk to the array, woud it be a better idea to stripe all three drives and just partition OS/Programs/Data? I'm looking for performance and fast renders because I hate to wai...

Comments

goshep wrote on 8/16/2007, 5:44 PM
First of all, don't kick yourself for the RAID 0 setup. You don't need redundancy, you need blazing speed. Your media is all on tape still anyway (at least mine is). I posed this same question a while back and even after bumping it a couple of times I got no response which is the first time ever I've struck out here. Sooooo, I tried an experiment. I ran a render test with all media on the RAID and rendering TO the RAID. Then I placed all media on a separate SATA drive and rendered to the RAID again. The project (which rendered in 2 hours 45 minutes on my old system) rendered in just over 7 minutes with all media on the RAID (on the new Quad core system) and a few seconds longer when rendering to the RAID with media on separate SATA drive. I assume any number of factors could cause a difference of a few seconds. I also assume that a much longer project (this one was about 30 minutes in length) might make a little more difference over time. However, given the lack of any official suggestions or appreciable difference in render times, I've concluded that any difference in performance is negligible. Perhaps these bold statements will draw out a more informed opinion. I would assume there is some bottlenecking occurring when moving the media from one drive to the RAID but again, it seemed insignificant in my tests.
rmack350 wrote on 8/17/2007, 10:23 AM
You need to decide on the balance of safety and performance you need. If you do backups every night and you know for a fact that you can restore a complete system from these backups then I suppose striping the whole thing is okay. However, you still want the data drive/array to be physically seperate from the boot array.

My own inclination would be to keep it simple and use a single drive for OS, programs, and user home directories, and then use the array for all video work. And continue with those nightly backups. Yes, it could be more "tuned" but there's a point where I just would rather stop fiddling.

The most obvious thing you need a striped RAID 0 array for is to be able to play uncompressed files, because they need a higher data rate than most single drives can provide. This probably also applies to cineform HD or to apples ProRes. You also need Raid0 when capturing via a Xena card to a fat file format. You might also want an array if you're playing multiple streams, I suppose.

Would it make a difference for renders? It really depends on whether your computer can render faster than it can write. That's most likely the case if you're doing uncompressed renders of straight footage, less likely as the CPU load increases. It hardly matters, since you've got the array and you're doing backups there's not much reason not to use it.

Well, maybe there's one reason. Most RAID controllers use the CPU. The overhead here may actually slow down your renders. Probably not much of an issue with a quad but definitely an issue with a single core system.

Rob Mack
farss wrote on 8/17/2007, 5:53 PM
It depends, certainly I'd leave the OS on its own drive.
For high datarate media such as DigitalBetacam you absolutely need RAID 0, SATA drives will be adequate. But there's a difference between how you get RAID 0, dedicated RAID controllers free the CPU up and from my experience are rock solid.

Bob.
rmack350 wrote on 8/17/2007, 6:18 PM
Yes!

I've seen a few eSATA RAID boxes and some of them run off of single eSATA cables. The RAID is handled in the box.

I think that the SATA interface has lots of bandwidth to spare and have been wondering if these would offload the RAID processing from the CPU?

Idle curiosity.

Rob
Troy Duran wrote on 8/18/2007, 11:00 AM
Hey guys, thanks very much for your input! I think I'll keep it like it is, with the OS and programs on one drive, striping the rest.
Troy Duran wrote on 8/18/2007, 11:00 AM
Hey guys, thanks very much for your input! I think I'll keep it like it is, with the OS and programs on one drive, striping the rest.
Troy Duran wrote on 8/18/2007, 1:38 PM
Hey guys, thanks very much for your input! I think I'll keep it like it is, with the OS and programs on one drive, striping the rest.
Sidecar2 wrote on 8/18/2007, 3:41 PM
Troy,

You definitely got my attention with the "2.75 hour render down to 7 minutes" comment!

Please publish your computer's specs:

Motherboard brand and model
Processor
RAM configuration
RAID controllers
Video card
Hard drive setup

SATA II (3Gbps) appears to be most capable.

I'm looking to buy a new computer and would appreciate knowing how your system is set up.

Thanks.