RAID question

[Nick]

My buddy is a musician and runs lots of audio software.
He has a good system (P4 3GHz, 4GB RAM) but reckons his disk performance holds back his PC. His disks are SATA 150. He's seen some cheap Samsung 500GB drives and a PCI-Express 1x SATA2 RAID card. So he reckons if he dumps his old drives and installs the card plus 2 of these disks in a striped array, he'll quadruple his transfer speeds.

My main concern is that a 1x PCI-Express card will not have enough bandwidth to do SATA2 RAID-0. Is this a valid concern?

Does anyone know how good the actual achievable performance of such an array is, and how this compares to PCI-E 1x bandwidth?

Problem is he only has 1x and 16x slots in his machine and his gfx card fills the 16x, so he can't use a 4x card. Would a 1x card and 2 SATA2 drives be worth his while?

[Shinigami-Sama]

hmmm...
I don't see how only two SATA drives could saturate the 1X pipe, the Satas could get burst speeds of 200MB/s at best, unless they've come a long ways in the two years since I dealt with RAID Arrays

now if he adds a third to the array I could see that causing some trouble with reliability mostly...
so no it shouldn't be much of a concern, but he'd better have a good backup plan if plans on using RAID-0, should tell him to pick up a thrid drive just to back up the important files too just in case

[Blue_MiSfit]

a 2 drive RAID array will push at most 60-70mb per second sustained. That's nowhere near saturating even PCI, let alone PCI Express.

His SATA150 drives aren't any slower than SATA300. He won't quadruple his transfer speeds by any means. If anything he will see a 20-30% gain, and only if he's copying between two identical RAIDs, because otherwise you're going to be limited by the other device (a single hard drive etc).

Two drives on a PCIe 1x controller is still fine. 4 is pushing it a bit, but not really. Beyond 4 you need a 4x slot for sure, and you can do up to 16 comfortably.

RAID is nice, but it's not as fast as you would think.

~MiSfit

[Nick]

Nice work guys.

I'll pass that on.

His mainboard supports SATA1 RAID. So if current HDD architecture is nowhere near fast enough to saturate the SATA bus, let alone a SATA2 bus, then there certainly seems to be no point in buying the extra hardware.

Perhaps a whopping external drive to back up his entire system to, then reconstruct his drive partitions in a RAID array and restore his backups. I wonder, if he backs up his Windows system drive to an image file on an external drive, sets up an array and restores the image from a Linux Live CD environment, will Windows book OK afterwards?

[Blue_MiSfit]

Definitely no point in buying extra hardware unless he needs a fault tolerant multi terabyte sized storage solution! :)

Good questions. Hard drive images and RAID seems tricky - though I've never done it.

I would have him back up data, not an entire windows volume. Easier to just have the data available, and reinstall Windows after a failure.

Honestly though with RAID 1, the chances of data loss are pretty slim :)

If he needs a faster PC, get him over to a Core 2 Duo. It's light years ahead of the P4, which will seem slow by comparison! Some really intensive synthesizer apps (like anything from Native Instruments) gobble up CPU power like candy.

~MiSfit