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Old 06-09-2008, 12:56 AM   #1
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NFS cpu usage

I've got a Fedora 8 computer acting as my NFS server. When I try to copy files to it from other computers on the network, I get a maximum throughput of 7.1MB/s (~56Mbit). At first I was very excited because this was much faster than my previous Samba based network storage (which would max out around 2.5MB/s if I was lucky).

However I looked more into why it was only 56Mbit instead of the full 100Mbit of my lan connection, and I saw with htop that my poor 750mhz server was maxing out the cpu during the file copy. Why would NFS require so much cpu to write a file?
Old 06-09-2008, 01:42 AM   #2
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NFS carries alot of overhead to run, there are quite a few processes to ensure integrity. The beautiful simplicity of NFS, using defined mountpoints over a network, in a stateless environment, means it is 'relatively' easy to compromise. Newer versions of NFS carry overhead to ensure they are always talking to correct client and user!

You can reduce this if you wish, look up the many posts on here....
Old 06-09-2008, 09:27 AM   #3
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Also check to make sure it's not your hard disks having high I/O issues. Usually from what I've seen, it's always Disk I/O performance issues that is the bottleneck. Basically look for high await % in top or running iostat to determine the issue. It could be that your CPU is waiting on the disks to write, etc.


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