View Full Version : low write speed
Hi,
I just created raid-0 of 2 120GB ibm w/ 8MB cache with stripe size 64kb. They are ATA/100.
Using on-board raid chip HighPoint 372 on abit kd7-raid.
The read speeds are very good. However the write times are not.
I used sandra and atto.
I uninstalled norton anti-virus thinking it would help...
Bellow are images of the atto results.
The test with overlapped i/o only shows good write speeds.
Even the cached (not direct-i/o) write speeds are slow!?
Anynody had similar problem or has any idea what may be the problem?
All tests use 32mb total size to avoid the disks 2x8MB cache.
Overlapped I/O:
http://pin.homeip.net/imgs/oc/atto-overlapped.gif
I/O Comparison:
http://pin.homeip.net/imgs/oc/atto-comp.gif
Neither:
http://pin.homeip.net/imgs/oc/atto-none.gif
Neither - cached (not direct-i/o):
http://pin.homeip.net/imgs/oc/atto-none-cached.gif
Please help!
Also - the OS is win2000 SP2.
The file system on C is 4GB fat 32 with 4kb cluster used only for the boot image and 1GB swap.
In device manager for the drive it is listed under scsi and in the scsi properties tab "enable write cache" is disabled (grayed) and unchecked.
Is this normal for write cache to be disabled?
Do you get similar results for write speed?
Skiing Squirrel
05-28-03, 05:41 PM
http://www.theforumisdown.com/uploadfiles/0103/benchniether.JPG
there you go bud. :)
Why are mine so low? What could it be?
Skiing Squirrel
05-28-03, 06:18 PM
Update drivers for card, or harddrives? Reinstall the raid array? I really dont know... Im not too much of an expert in this field.
Why didn't you match the Stripe & Cluster sizes? Since W2000 allows you to do this with relative ease I expected that you would have done it. I don't think your scores are so low but they can definitely be improved. What is the PCI Latency set at in your BIOS?
See the 3rd image - all write speeds are about 4MB/s. Which is very slow.
The speed grows with the transfer size:
0.5 - 3200
1 - 6500
2 - 12700
4 and all others - 4000
and then it drops to 4000 and stays there.
Why it doesn't grow up to 12000 and then stay there but instead drops to 4000?
Also why the overlapped shows good results?
I will try on different volumes with bugger clusters and different FS (NTFS) to compare.
But Skiing Squirrel is getting normal results - they grow with the transfer size and are way better then mine (on write only).
I am still at work - will check later...
Skiing Squirrel
05-28-03, 07:33 PM
I got a question. Is it fast in regular applications?
I am not sure how to check. I think it is not because pcmark also showed slow write times and it uses regular test like compressing and disk copy...
Before time it was ok - the write times were good. At some point it broke... maybe after I updated the bios or installed norton anti-virus... not sure - found out too late...
Btw, Sonny, do you know if kd7-riad have HPT 372 or 374 chipset?
I am not sure which drivers to use to update. On abit site it says that the latest bios updated the HPT to 374...?
If this is the case then drivers update may fix it... will check in an hour...
It seems the chipset is 372.
The questions is the bios version - is it 2.32 or 2.34?
It's the HP372 RAID Controller. Which BIOS are you using, still on that modded one from Tmod? If so that should have the 2.34 RAID BIOS.
I just rebooted - it is 2.32 - I didn't flash the modded bios - just the regular kd7dn.
The drivers are 2.32 so I won't update.
Any other ideas?
Should I update win2000 from sp2 to sp3 ? Would it help?
Set the PCI Latency to 128, recreate the array, match cluster size then reinstall. Try 16K Stripe with 16K Clusters on NTFS. SlipStream SP3 already.
I changed the pci latency to 128,
installed sp3
installed via 4in1 4.47
no change... :(
Is it safe to update hpt drivers to 2.34 when the hpt bios is 2.32?
If I want to update both which do I start with?
Did you match the Stripe & Cluster Sizes yet? Stripe & Cluster sizing happens to be the most effective way of influencing change in performance when it comes to RAID Arrays. What seems to bench the highest are 16K Stripe & 16K Cluster but actuall speed varies with the kind of work you do with the array. Ask yourself if you really find it slow during realworld duties & not benchmarking.
Safest way really is to FLASH the BIOS then Reinstall then update drivers to match.
Read this thread (http://forum.abit-usa.com/showthread.php?s=&threadid=8320).
It seems not only I had this problem with the latest bios kd7dn.
It may be the cpu disconnect function...
Or I may need to install the modded bios...
I doubt it but if you feel that's the answer then good luck:beer:
Yes!!!
See this:
http://pin.homeip.net/imgs/oc/atto-none-new.gif
The only thing I did was to disable "CPU disconnect function".
Which was added by the latest bios kd7dn and enabled by default.
My explanations is:
onboard raid uses the cpu to transfer data. The transfering itseld is done by DMA but when it finishes it takes time to initialize the cpu...
anyway now it works great - you can see the diff.
Now even sandra shows good write times. PCMark also.
sandra show 59MB/s total index.
Thanks for all advises.
I didn't even thought it may be bios settings...
Now it works so great!
What do the Overclapped I/O scores look like?
Exactly the same - within the test error margin:
http://pin.homeip.net/imgs/oc/atto-overlapped-new.gif
The drives are ATA/100 so 100 MB/s should be the max for them even with internal cache. Now wouldn't the total max be 200 MB/s or what is the raid controller / southbridge max ?
Anyway, the raid speed is a lot better then I expected or even hoped!
I am so glad I tried it...
Now the raid will be able to handle dv-camcorder - the firewire would be the bottleneck...
So within the same Overlapped I/O test the scores are the same. What I am wondering about is if ATTO is getting confused or not. Do you have a large, 1G, file to check for transfer speeds? Copy from one partition to another & time it, see if there is an actual difference. I do a lot of capturing from my camcorder & I never had any problems.
See the pc mark hdd results:
slow writes (http://service.futuremark.com/compare?pcm=1313353)
fast writes (http://service.futuremark.com/compare?pcm=1325548)
See the write transfer rates - it is using "real wourld" copy.
My cpu is almost never idle (folding 24/7) so I really don't need the cpu disconnect option to be on. It reduces themp only when idle...
If your happy that's all that matters, not that I think PCMark holds any water;)
yea - me too (about pcmark)
I am happy with it now. :D
The thing is the problem existed even with the non-raid drive - the write scores dropped a lot in sandra but I didn't care.
When I made the raid array and the write speed was the same low then it was a problem.
My main goal is what time would take to non-optimized program to read and write data to hdd. Now 10% slow down is ok, but from 70MB/s to 4MB/s is 17 times slower!
Anyway, now I am happy with it and won't even bother to test more... ;)
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