Syba/Silicon Image - SIL680 Raid
Most of the new motherboards are offering built in raid solutions. I've also seen a lot of PCI based raid cards. My motherboard (a Tyan Tiger MP) does not have a built in raid solution, so I bought this cheap PCI raid card off of the web ($19 shipped) and found 4 identical Seagate drives on ebay (Model ST320013A - 20 Gig, 7200RPM, ATA 133) to test it out with.
I wanted to answer the following questions:
How much faster is raid 0 (Striping)?
Do I need a raid controller card, or is Software raid sufficient?
Does it make a difference if I have 2 drives on a cable or is it faster with a single drive per cable?
How do the cheap PCI raid cards work?
To start off, I decided to do some baseline tests to see how fast the hard drives were without any form of raid or mirroring. Using my motherboard's on board IDE Ports, I installed the drives, put an empty NTFS partition on them, and ran SiSoft Sandra to see how they rated.
I included a GOOF on my part in the results here. My first run of benchmark speeds was done with the drive’s jumpers unchanged from the factory. Later I discovered they were set to Cable Select. I would have not believed it, but simply jumpering the drives as master or slave increased speed by about 145%!!!!
WinXP Pro has built in software raid (striping) It works by writing 1/2 of the data on the first drive and the other half on the 2nd. (or 3rd’s or 4th’s with more drives) I created a striped volume and again ran Sandra’s file system benchmark.
Now I am seeing some speed increase. 2 drives sees a 131% increase over a single drive, 3 drives sees 150% increase over a single drive. I could not include the 4th drive because I had to keep the operating system drive on the primary master channel.
First off, when I started with the raid controller, I again hooked up the drives one at a time and checked single drive speeds. They were consistent with the host controller’s posted speeds. I then used the raid card’s built in striping features.
As you can see the overall winner is a 4 drive stripe set at a 213% increase over a single drive’s speed. Looking at this from a cost perspective I’d choose the 2 drives on separate cables, as it gives you better performance per drive, and is still a whopping 190% increase over a single drive’s speed. Surprisingly the 3 drive configuration is actually slower than the 2 drive configuration, so I definitely won’t be putting that into effect on a permanent basis.
So, have I answered my questions? Lets see if I can answer them now.
1.) How much faster is raid (Striping)?
Up to 213% faster with 4 drives in the raid set.
2.) Do I need a raid controller card, or is Software raid sufficient?
Software raid does increase the speed, but I’d tell anyone to spend $19 US dollars for better performance
3.) Does it make a difference if I have 2 drives on a cable or is it faster with a single drive per cable?
Having a single drive on a cable very much helps increase the stripe set’s overall speed
4.) How do the cheap PCI raid cards work?
I couldn’t be happier with this Silicon Image SIL-680 based card. It provides faster access to my data, and definitely increases speeds. I do have one gripe though; the stripe sets do not work under Linux. I can use the drives as single drives in Linux, but I am unable to use the raid features of the board with that OS.
I will probably be doing a similar review including Mirrored sets and 0+1 (stripe and mirror) results.
Hey, this isn't something I do every day, but will probably do more often. If you have any thoughts on stuff i could do differently, feel free to let me know!
