DL100 NAS Poor Transfer Rate

[SteveCDN]

I'm seeing poor performance transfering a 40GB file on a gig network to the DL100 NAS running Windows Storage Server. It takes approximately 180 minutes to transfer this file. If I try to transfer from a server to an HP PC, it take approximately 25 minutes.

Can anyone confirm how long it takes to transfer a 40GB file on their gig network to the NAS?

We're working with HP support, but it's taking a while to convince them this is a problem.

Thanks.

[Rob Leadbeater]

Hi,

Something isn't right somewhere. If everything were running correctly at 1Gb/s then it shouldn't take more than 10 minutes.

Less if you believe tools such as this download calculator:

http://www.t1shopper.com/tools/calculate/downloadcalculator.shtml

which says a bit over 6 minutes.

Can you check on your switches that everything is synced up properly at 1000 Full Duplex ?

Hope this helps,

Regards,

Rob

[SteveCDN]

Seems like that calculator is a little ambitious. I re-tested and my initial post was wrong, it took 86 minutes for 40gb to the NAS while it was about 20 minutes to a regular HP PC.

Thanks for the idea, but the switch is OK and is working at 1gb full. We just swapped out the NAS for the PC using the same cable and ports and see the increase in performance.

I'm checking with HP, but hopefully the performance of the NAS should be better than this...at least as good i/o as a PC, otherwise it's not going to be very useful as a disk to disk backup.

Steve.

[Jon Paul · Accepted solution]

Hi Steve,
Sorry to say, I believe that this is the correct performance. The Gb NIC can transfer far more data than the RAID controller.
You can make tweaks to the File system that will improve performance. And you can enable the Write-Cache in the Adaptec RAID controller, but this can lead to data loss in a power failure.
RAID Controller tweaks:
- Re-Create the DATA drive with as large a stripe size as possible
- Enable Write Cache (Note warnings about data loss)
File System Tweaks:
- Reformat the NTFS partition with a 64k "Allocation Unit Size"
Of all these tweaks, the enable write cache will have the biggest benefit but it does make your data vulnerable since data can be in the cache during a power loss.
Since you are using very large files, you will want the larger stripe and allocation sizes for the speed and should not be concerned about the loss of space from files not quite filling the stripes or allocation units.
You can use a program like IOMeter (www.iometer.org) to run locally on the system and get the max transfer rate to harddrives (which is going to be your bottleneck) A file which is 2x the size of your system RAM will "defeat" all caching on the system and should give you a true reading of the max throughput.

Hope this helps,
Jon Paul

[SteveCDN]

Jon Paul, your answer was right on. I enabled the write cache for the controller and the transfer rate immediately improved. Transfering a 40GB file went from 86 minutes to 23 minutes. I have a UPS on this NAS, so no worries on power loss.

Thanks.

[SteveCDN]

enable write cache on the NAS Adaptec controller for the logical drive.