RAID Array degrading fast?

[Someone]

Hello everyone:

Im in kindof a pickle.

After Christmas i re-installed everything, ran a benchmark, and the array was transfering 45000k/sec.

I have made no changes and now it is to 22000k/sec.

here are some specs

P4 2.4 @ 3.0
ASUS P4SDX Motherboard
1 GIG Corsair Twinx LLPT Ver 1.1
4 Seagate Barracutas SATA
PRomise FastTrak S150 SX4 w/ 256 megs Non EEC

The benchmark is Sandra, and here are specifics:
Buffered Read 1007 MB/s
Sequential Read 31 MB/s
Random Read 9 MB/s
Buffered Write 2659 MB/s
Sequential Write 33 MB/s
Random Write 11 MB/s
Average Access Time 5 ms


When i first built this system i was getting 40000 k/sec and in less than a day it dropped to 30000 k/sec so i looked around and found a few settings.

I changed the " Write Mode " to " Write Back ", and that improved it some.

I also ran a synchronization option thinking that it would help, but it didnt...

Im clueless, any ideas why the array is starting to loose is pep?

Thanks in advance


Marc Holcombe

 

[FireMogle]

Have you installed anything onto the machine since then? maybe some seriouse fragging has happened? I dont trust sandra anymore but that does seem like an odd problem though.

 

[stan03]

i thought the more you put on the drives the slower they get?? it happens with me also.

 

[Someone]

I defraged the drives, and the problem got worst

Also, each drive is 120 gigs, i have 4 in a raid 0 + 1 array, with a total of 240 gigs. I only have 31 gigs used. If the problem is that the array slows as more is added then by the time im at 200gigs of data i will have a score of 200 k/ sec

I dont think thats the problem. I did however change the cashing mode back to "through", restarted, then changed it back to " Back " and got a score around 32000 k/ sec...

Its better, but still not near the 40000k / sec + i should be getting.



I dont know... maybe i should just re- install again?

 

[stan03]

did you restart? i need to restart after each defrag or my score drops also.

 

[Deliximus]

i'm thinking of getting one of those cards.
however, i can't find a review on it.
how much difference does the ram make??

 

[Someone]

ram is required, so performance is way way better with it

I dont want to say the card sucks though because it 'works', just doesnt work near as fast as it sould though, but i do not believe it is the card.

I think something else is causing the slowdown. There is one thing about it i do like though.

I am in a raid 0+1 setup with SATA ( Which is a very stupid design!) when one of the power connecters sliped off... ( Stupid design!). The array was critical, but all i did was plug it back in. " computer running and everything " and the array automatically rebuilt itself. Very nice indead


Still though, I spent alot of money on all this, and wish that i would be getting the speed i should. If i knew it would be this slow i would have went with one seagate cheeta, would have been faster.


My recomendation...

If you are going to do any raid array, buy a motherboard with PCI-X, or wait for PCI Express... That is what raid is designed for, and there isnt enough bandwith in a regular PCI bus for the raid array, sound devise, nic, and everything else that hoggs bandwith. there just isnt enough bandwith, its like a 4 lane highway all merging into 1 lane, but luckly no wrecks yet.

 

[Max47]

Still though, I spent alot of money on all this, and wish that i would be getting the speed i should. If i knew it would be this slow i would have went with one seagate cheeta, would have been faster.

actually i have heard from so many people that the RAID0 arrays degrade after more storage is used, time, defrags, and restarts... I have yet to get the drives to set one up and experience it for myself but i am thinking of not even fooling with it either that or just making one for the OS. it seems as they fast for a limited time... which is a waste of a decent amount of time and a large amount of money..

 

[stan03]

well they remain faster than single drives, and he seems just to be expiriencing very large losses in performance, i have losses, but to a much lesser extent.

 

[jamespetts]

You could try checking the health of your drives: in a RAID 0+1 array, it would only take one drive to start going slow to affect the speed of the whole array. Run a SMART tool on all of the drives. If any of them come back with lots of reallocated sectors, or high raw-read error rates, then it might need replacing. Also, check the UDMA levels of your drives: they should all be mode 5 at least.

 

[Someone]

What type of SMART tool?

and how do i check UDMA?


I appreciate the advice. These both seem interesting ideas because i havent done either, and they both do make since.