Crapy Raid Performance?

[safan80]

The only use SATA 2 has for raw performance is with the RAM drives.

anyway, while I would love 2x150gb raptors or even the 74g's its not worth the money to me. (not that I have it currently)

For setting up your stripe size you might want to check http://www.techspot.com/vb/topic1596.html

I may have discovered a formula for determining an appropriate stripe size.

If you go into XP disk defragmenter and click on Analyze for your array, it should return a value of the average file size.

Take this number, and divide it by 2 x # of harddrives in the array, then round DOWN to the nearest available stripe size you can choose.

Let's assume that the average file size on your harddrive is 512Kb.
Divide that by a factor of the above calculated number. In my case, I have 4 harddrives in my array, so I would choose 8.

So, 512Kb divided by 8 = 64K (the optimal stripe size for my average files).

Let's say you had 2 harddrives in the array, then using the above formula, you would choose 128K stripe size.

This is contingent on whether you are just storing data and seldom using it or are actively using the data. If just storing Data, then put the operating system on it's own harddrive, not on the array. OS=small stripe size, data=big stripe size in your case.

Another important OVERLOOKED factor is the Cluster Size of the formatted harddrives.

In my humble opinion, I would set the cluster size for 1/2 of the stripe size when formatting. This should reduce disk fragmentation and can appreciably decrease drive maintenance.

I have done several experiments, and smaller stripe sizes for the OS can make it really fly! But with smaller stripe sizes, you also have to defragment daily (not my cup of tea). Personally, I am using a 64K stripe with a 32K cluster. My fragmentation is pretty normal as opposed to a single harddrive. And I wouldn't suggest going with any stripe size less than 8K - you go from extreme speed at first to a snails pace in a few hours of heavy use, without defragmentating. Highpoint can let you go lower than that, and up to 2048Kb if desired.

It works quite nicely except on boot up, but that could be the umteen things I have running...

I would experiment further, but I wore out my XP disk and had to buy another one - lol. And Microsoft doesn't like it when you have to keep activating numerous times for your experiments.

To the guy with the MP3's and such, I suggest the following combination -

4Mb average filesize = 512 stripe size
Cluster size when formatting under XP should be 1/2 x 512 or 64K cluster size (max cluster size allowed under XP).


This should give you very nice performance and you shouldn't have to defragment too often.

By all means, email me. I would love to hear how well this works for you.

I was meaning the proformance of current sata2 based hard drives like the seagate 7200.9 series drives with 16MB cache in a raid0 setup and the not sata2 standard. However, speaking in terms of the standard the sata2.5 standard has hotplug and staggered spin up the latter which is useful when your dealing with a lot of drives. a good controller card is also worth getting because the nv controller doesn't have any onboard cache. I'm using an areca pci-express sata2 controller card in my other system and it is very fast to say the least.


you want to see large fast arrays go to http://forums.2cpu.com/ in the storage section.