We are using an NFS mount and need to transfer 200 Mb and larger files via this mount. Both NFS and FTP cause the I/O to max out. We've tested several scenarios and have determined it is indeed LINUX that has the issue. Is there a file size limitation here? We have a case with Red Hat but need this resolved ASAP as this affects our financial systems.

Thanks for your help!

Not seeing this issue on Fedora (I've transferred files 10's of GB over NFS), so there must be an implementation issue. 200MB files are pretty small by today's standards.

We've done this test on different Linux boxes to eliminate the hardware and installation methods. I installed Linux using all the defaults on the test box and our production box was installed by a vendor installer. Same issue on both boxes. The similarity between the boxes is that they are both using Red Hat 4. Do we need to enable large files in the kernel or is that the default setting?

I'd guess that you're hitting a driver issue - either the
network-card or the disk subsystem one. Check whether there's
a newer kernel available. What hardware is this on? What
version is your kernel?



Cheers,
Tink

Tink,

We've tried this on 2 completely different hardware forms. Even the nics were at different speeds. Smaller files don't touch the I/O at all, but a 200 mb file puts I/O at 100% and locks up the system. We are running 2.6.9-42.0.2 which was the most recent Kernel as I understan di.

Are you seeing anything in your syslog or dmesg just prior to the problem occurring?

Not seeing anything unusual. I found in another thread where this is occurring for other people as well. I wonder if it is a known issue and Red Hat is working on it?

You may want to do the following:

-Boot to a LiveCD on both systems with a newer kernel such as Knoppix. Mount the folders and then try the transfer. If it works then you'll know that it's your software and not your hardware. If it doesn't work then it could be your hardware.

-Use 1000 Mbit/Gigabit NIC and Switches.

-Try using a null network cable to narrow down any switch or network problems.

-Even better, try it over a fiber connection.

-Try compressing the file as you send, you can do this using ssh and rsync.

-Try compressing the file before you send.

-Try splitting the file in chunks of 2GB as you copy. Afterward you can contactenate each chunk into the one big file. You can do this using the dd and split commands.

-Copying one mega file this big may cause overruns and errors. Think about it. Your system has to verify a all the bits in a 200GB file. This is one way of making your system get on it's knees.

ramram29,

All good suggestions, but we need to resolve the issue as is because the NFS mount needs to go to a 10/100 nic on a VMS server. We've eliminated the hardware so far and have isolated it to Red Hat software. We just need to find a way to successfully transfer 200mb and larger files using NFS from our LINUX 4 to a VMS server using NFS 2.

MACEMONETA,

What is the kernel version of Fedora and what is the RPM for NFS that you are running? Might help us.

Fedora tends to run well ahead of Redhat:

kernel-2.6.20-1.2925.fc6
nfs-utils-1.0.10-5.fc6