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P5WD2 Premium RAID Problem - Help!

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Leica

Member
Joined
Feb 7, 2005
I just got FOUR beautiful Seagate 500GB 7200.9 drives (which cost me an arm and a leg).

I am running them in RAID 5.

They run fine, EXCEPT they are very very slow. The write speed in particular is about 5-10 times as slow as my single WD 250GB drive.

Clearly something is wrong. What could it be?

Thanks.
 
My guess is that you are using the onboard Raid? If so, I doubt that it has a built in Processors for XOR support. Thus, all calculations are being done by your main CPU. Have you played around with different drivers? Have you run ATTO Benchmarks? Or HD Tach? Maybe post some screenshots of these. What are your Read/Write speeds?
 
Well the readings from both those benchmarks is very erratic. Somethings it writes at only 3,000 KB/s sometimes at 200,000 KB/s

My stripe size is 64KB for the array.

But when I try to write files to the RAID myself using copy or other means it is very, very slow.

Thanks.

P.S. And yes I am using the onboard ICH7R RAID. But I have a Penitum D (dual core) running at 3.7GHz.
 
I don't know how to save the graph from ATTO so here are the values:-

Transfer Size/Write/Read
0.5/5571/15944
1.0/22104/27238
2.0/7189/41303
4.0/6650/50973
8.0/5592/62757
16.0/5377/74263
32.0/4993/95182
64.0/5167/75497
128.0/6103/74935
256.0/7821/99913
512.0/7124/79940
1024.0/7783/79351

All four drives have been tested induvidually and they all work fine on thier own.

The above are with Write Cache OFF for both the drives and the ARRAY.

These are the readings with Write Cache ON for the drives but OFF for the ARRAY:-

0.5/23/3757
1.0/50/7059
2.0/89/11956
4.0/198/22211
8.0/390/36068
16.0/724/85768
32.0/1240/127926
64.0/1654/168820
128.0/1762/190364
256.0/1827/180951
512.0/2573/190364
1024.0/2719/189318

Finally here are the values (very eratic!) with BOTH Hard Drive and ARRAY WRITE CACHE enabled:-

0.5/23/3757
1.0/50/7059
2.0/89/11956
4.0/198/22211
8.0/390/36068
16.0/724/85768
32.0/1240/127926
64.0/1654/168820
128.0/1762/190364
256.0/1827/180951
512.0/2573/190364
1024.0/2719/189318
 
Well, being that it is Software assisted Raid Array, I am not surprised by your write speeds. I cannot comment on that specific board, but in my experience, onboard Raid 5 will be slow feeling due to its sharing of the CPU for processing needs. Your best bet for that large/type of array, would be to get a True Hardware Raid5 controller.

Like I said though, I don't have experience with that board, so I could be wrong about that looking normal. I would wait for someone else who has a raid5 array setup on that board.
 
Well I abandoned RAID 5 and switched to RAID 10. Sadly I get much less storage and my cost per GB is sky high, but the thing flies now :) And it is fully redundant too!
 
BigStan said:
I thought RAID 5 neede 5 drives. 4 for RAID and one for parity

Raid 5 works on 3 or more drives ... it spreads parity across the drives. So three drives get you 2 drives capacity ... 4 gets you 3, etc

I am glad to see someone has tried the ich7r's raid 5 support before i do.
It will help me from getting my perf expectations too high.

I expect to be trying it out soon on a p5wd2 premium/non or possibly on a p5ld2 board, maybe with an 830 ... for my new main rig ... but it seems a waste to run an awesome folder like the 830 at 'stable for work' speeds with probably only one instance ... so maybe i will try it with a 551, or even a 531 ... still more than enough for 'work' ... and once i bench folding between the 955 and 945 chipsets, wouldn't be surprised if i use the ld2 for work and leave the others to mostly dedicated folding.

The perf compromise for raid 5 will hopefully be a reasonable one. If not i will try an add-in raid board (had great experiences with cheap SI chip based raid 0/1 boards on older p3's).
 
BigStan said:
I've got an extra one of these I'm not using. Might let go of it reasonably someone twisted my arm gently.

I already have a premium and a non-premium. They are just folding right now. I am going to to get a p5ld2 (non-deluxe ) so I can do some folding benchmarks with my 2'nd 830 between chipsets, mem combos, etc. before i settle on the board for my 3'rd 830 (assuming i keep it).

I will keep you in mind tho ... although getting mobo's cheaply through customs to canada does cut into any price advantage.

My cheapest local source here is p5ld2 - 148, p5wd2 - 217, p5wd2-p - 242 ... all CDN$ of course. I pick up around the corner so no shipping but I pay 15% sales tax (cross border can also cost 8% tax on declared value).

Right now I have a 551 in the p2wd2 premium ... I don't expect to see a folding diff when i swap the 830 on a non-premium with the 551.

Am interested to see if there is a significant difference between the LD2 and the WD2 for my folding (QMD) benchmarks single and dual instances.
So far the 830 at 255 does around 800 ppd 2 instances folding, vs 710 on the 551 at 250. Temps are comparable on air ... 551 will reset much over 62, 830 gets unstable above 64. both are running 60-62 now stable.

Plan to run them on water long term (once i get a second wc system setup.
Also have a prommie to play with but doubt it will go far with the 830's heat ... but the 551 should be fun.
 
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