Fog Creek Software
Discussion Board




RAID for developers

I have a new environment, and would like to set things up right.  I have 2x 80 GB drives, and am considering setting up RAID on these two drives.  Since I'm not using the SCSI controller with built in support for RAID 0, I'll probably have to use a software built in to Win 2003 Server.  Anyone had experience with this?  Is it even worth it?

Thanks

nathan
Saturday, August 16, 2003

Okay, here's the ugly truth.

Most of these "cheap-o" RAID cards are actually doing a lot in software. For example, all the sub-$300 Serial ATA RAID cards are actually doing the bulk of the RAID in software, including the ones built into the motherboard (such as the ones from Intel or Silicon Image).

The software RAID in Windows 2003 is VERY solid. It's been around for ages... at least as long as NT 4.0. It won't perform like one of those $400 RAID cards w/ 64MB of RAM on them, but you get what you pay for. As a data protection (from drive failure) mechanism, it's great.

Don't run RAID 0 (stripeset) or JBOD. They don't protect data. You need either RAID-1 (mirror), or RAID-5 (stripeset with parity), or RAID-10 (sometimes called RAID-1+0, which is a mirrored stripset). For a typical developer, two identical drives in a RAID-1 mirror is what you'll use. (Theoretically) half the speed on writes, but double the speed on reads, because it can go to either drive to fulfill the read.

Brad Wilson (dotnetguy.techieswithcats.com)
Saturday, August 16, 2003

I use software RAID 1 for my Win2K server.  Seems to do the job just fine.

When one of my employees broke in to the server room last year, he rebooted the server in a failed effort to get some banking information (though he did manage to steal some checks).  In any case, the primary drive became unbootable, but the 2nd drive kept the data just fine and we were able to rebuild the RAID.

Ankur
Saturday, August 16, 2003

Also he would need more drives to use raid 5

Mike
Sunday, August 17, 2003

Also note that software RAID-5 is a decidedly awful performer because it's more complicated than RAID-0/RAID-1.  If you are doing RAID-5, it's probably best done with an intelligent controller.

The best part about software RAID is that you can combine types on the same drive.  Allocate 20 gigs on each drive to a RAID-0 set that's really fast for temp files and such.  Allocate the rest on each drive for a RAID-1 set that is slower, but safer.  Hardware RAID doesn't do that. ;)

Flamebait Sr.
Monday, August 18, 2003

Oh yeah, and RAID-0 isn't theoretically half as fast for writes.  Done properly, it's at most a few percentage points slower.  Remember that most of the delay is the drive working on the write, not the IDE controller sending it.  So the controller sends the write command to both drives and they both crunch on it the same time.  And if you've set things up properly, you have each drive on a seperate IDE channel, so there's no bus contention.

A good spot to look is http://www.storagereview.com/ .

Flamebait Sr.
Monday, August 18, 2003

fyi - i went with RAID-1 using the software in Windows Server 2003.  works like a charm.  :)

nathan
Thursday, August 28, 2003

*  Recent Topics

*  Fog Creek Home