slow raid 0

quantumisation

quantumisation

quantumisation

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Joined
24 Feb 2007
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275
hi i have 2 7200.10 baracuda drives (320gb) in raid 0 using the onboard p5b controller. I ran HDTune (ill post a picture later) but the results were very low considering typical speeds of a single drive:

Minimum: 39.1 MB/sec
Maximum: 61.5 MB/sec
Average: 58.3 MB/sec

Access Time: 12.8ms
Burst Rate: 121.6 MB/sec
CPU Usage: 5.8%

Question is what could be causing this? i was gonna post this in the benchmark thread but im sure theres something wrong here. I dont mind too much cause i dont really notice it but the fact is theres not much point in me running raid 0 if it gives absolutly no increase in performance right?
 
There is definitely something wrong with those numbers although without seeing the full output from HDTune/HDTach it's difficult to say what is up.

You should be seeing an average transfer rate in excess of 110Mb/s.

Which P5B board do you have (there are umpteen different ones) and which SATA ports are you using for the drives?
 
im not sure if its 100% accurate cause i cant get HDtune to work now, its vista 64bit so probably isnt compatible..just says no drives found now. Anyway it does seem fast but who can say. Im using ports 0 and 1 on the motherboard, its a p5b deluxe and its using the intel controller not that other thing
 
well in the main bios everythings at its defaults atm except changed ide to raid, and in the raid bios just created 2 raid 0 drives with 128k, 2 other drives in the system are non raid
 
Just to clarify what you're saying above, did you create a single RAID0 array with 2 disks in it or 2 separate arrays, each with one drive? Or in other words do you have what looks like a single 640Gb drive attached to the PC?
 
This could be the problem.

Your Data Speeds look like a HDD without RAID. (even as a drive they still look slow).

There are 2 types of RAID 0

Striping & Spanned

In a stripe RAID setup, the RAID will write a little bit of data to each drive in turn. The cool part is that it can write to all disks in the RAID at the same time. Because of this a user will see a speed increase for every drive added to the stripe.

Spanning, on the other hand, will write to one disk until it is full and then begin on the next disk. Someone might choose spanning if they have hard disks of different sizes but for some reason would like to treat them as one volume.

So you could have made youre RAID 0 Spanned.
This means that you will only be using the bandwith of one drive instead of the bandwith of 2 at the same time. Hence the Data Speeds of what looks like one standerd Drive without RAID.

Hope this helps.
 
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