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Poor RAID Performance

Last response: in Storage
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July 10, 2002 4:11:18 AM

I have a two disk RAID 0 array that doesn't seem to be performing very well, and was wondering if anyone might have some hints on whether or not I miconfigured it, or what else I might be able to do to get better performance out of it?

Setup:
1.2 GHz Athlon
256MB RAM
A7V133 with an integrated Promise ATA100/FastTrack 100 RAID controller
2 x Maxtor ATA100 7200RPM 40GB HD (formatted NTFS)
WindowsXP

Unfortunately I had to use the drivers from Promise that are meant for the PCI version of the FastTrack 100 since Asus hasn't released RAID drivers compatible with WinXP.

Also, when configuring the drives originally I chose the "Desktop" configuration (the setup didn't allow me to manually set the block size other than to pick one of three options, desktop sounded the most appropriate and have no clue what size blocks I ended up with.

Anyway, here are some benchmark results I got from SiSoft Sandra 2001se Pro: (I was kind of expecting better results; think these are acceptable?)

----before raid----
40GB Maxtor 5T040H4 (NTFS)
Drive Index 22931
Buffered Read 50 MB/s
Sequential Read 33 MB/s
Random Read 6 MB/s
Buffered Write 35 MB/s
Sequential Write 32 MB/s
Random Write 8 MB/s
Average Access Time 9 ms (estimated)


----after raid----
RAID 0 2x 40GB Maxtor 5T040H4 (NTFS)
Drive Index 29720
Buffered Read 45 MB/s
Sequential Read 47 MB/s
Random Read 6 MB/s
Buffered Write 29 MB/s
Sequential Write 31 MB/s
Random Write 12 MB/s
Average Access Time 9 ms (estimated)


Sean74

More about : poor raid performance

July 10, 2002 5:00:20 AM

Hmm, you sequential read incresed but all your write times got worse... I would start by figuring out what stripe sizes are available then selecting the best one. There must be somewhere to find out what "desktop" stipe is?!
July 10, 2002 2:29:02 PM

If your stripping is set to high say in the triple digets, then youll see this problem. For example if you have striping set to 2k, then 4k with be spit to 2k, and so on, but anyting larger say 256, then your block size would be 128k slowing down both drives. this works the same if your stipe is too high, youll read time will be higher but if your not piping in that enough data to make use of the high striping then youll see a lack in preformence.

-Tim

It seems that every time I reboot my wallet get smaller.
!