Write speed problems over NFS (only one way though)

deflin39

I'm gonna try to explain this the best I can. First some stats info.

I have two boxes:
Bart:
P4 2.53 1gig
/dev/hda -> WD 30gig 7200
/dev/hde -> WD 30gig 7200 (through pci expansion card)

Moe:
AMD 600 256megs
/dev/hdc -> WD 20gig 5200
/dev/hdd -> WD 80gig 8M buf 7200

All connections have the proper UDMA IDE cables.

I have moe:/dev/hdd1 exported NFS to bart:/mnt/pub1

Here is the problem. It takes almost 4x longer to cp or mv a file from bart->moe than moe->bart

texas1emt · Posted: Wed Feb 02, 2005 2:58 am Post subject:

You might want to check that you have async in your /etc/exports on both machines. That will speed up things a great deal on the machine that's slow, if that's the problem.
_________________
M. Hayden - San Antonio, TX

JjcampNR · Posted: Wed Feb 02, 2005 3:05 am Post subject:

One other thing to keep in mind is that the performance of a PCI expansion card is no where near what a drive would be able to perform at if you had it directly into the IDE/SATA bus. That being said, you need to consider the possibility you're maxing out your PCI bus.

How many devices are running on the same PCI bus as your expansion card? If you're running ethernet, sound card, expansion card, etc. through one bus you're probably going to suffer some slowdown because the PCI bus may be maxed out. This may be the case if the files you're trying to copy to the other box are mainly located on the drive that's hooked-up to the expansion card. Since you're pulling files from a drive, through the PCI bus, and over ethernet which may also be on the PCI bus I'm sure traffic on that bus is getting congested.

Try swapping your drives around and see if that helps (ie put your system disk on the expansion card and the storage disk on the IDE channel). If this fixes the problem you'll know what's wrong, although leaving your system disk on the PCI bus isn't really great from a performance point of view.

--Josh
_________________
Damn the man, fight the power!

http://www.torquenetworks.com

texas1emt · Posted: Wed Feb 02, 2005 3:07 am Post subject:

Good point, JjcampNR. I didn't even think about that. :-)

_________________
M. Hayden - San Antonio, TX

JjcampNR · Posted: Wed Feb 02, 2005 3:11 am Post subject:

Thanks! Let us know if it works better switching the drives around or adding async to /etc/exports. If things are still slow I'll do more brain storming.

Another thing I just thought of is check to make sure DMA is actually set on the machine that's running slowly. Although you may have cables and have it set correctly in the kernel, you may have to use hdparm to turn it on.

--Josh
_________________
Damn the man, fight the power!

http://www.torquenetworks.com

deflin39 · Posted: Wed Feb 02, 2005 3:20 am Post subject:

In the test above, I did not involve the drive on the PCI expansion card, I was using the drive on /dev/hda. Though using the drive on the PCI expansion card yielded similar results (The only other thing on my PCI bus is a sound card).

I will add the async option and report back, however I read that async is not the default behavior anymore due to possible loss of data during power faults.

deflin39
_________________
The musicians today, who don't do drugs, and in fact speak out against it-"We're rockers against drugs"-boy, they suck. Suck. Ball-less, soul-less, spirit-less, corporate little bitches, suckers of Satan's cock, each and every one of themBillHicks

texas1emt · Posted: Wed Feb 02, 2005 3:24 am Post subject:

deflin39 · Posted: Wed Feb 02, 2005 3:29 am Post subject:

texas1emt · Posted: Wed Feb 02, 2005 3:34 am Post subject:

I use NFS w/async all the time... it would have to be a TREMENDOUSLY unlucky power outage during the exact same time you're making an NFS transfer.
_________________
M. Hayden - San Antonio, TX