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Old 01-13-2004, 07:46 PM   #1
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Location: Los Angeles, CA
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Can you rate your nfs performance with this command for me?

time dd if=/dev/zero of=/path_to_nfs_drive/testfile bs=16k count=16384  (writes a ~256M file of 0's through nfs) 

time dd if=/mnt/path_to_nfs_drive/testfile of=/dev/null bs=16k
I'm getting about 24 s on the write (the first command)
and about 20 s on the read (second command).

If you're getting anything vastly better than this, can you give me the details of your /etc/exports on the server and the /ets/fstab on the client that connected to it?

I'm runing all gigabit (nics and switch), but getting the speed of a 100 base-T (almost). I'm trying to see if it's just me or if nfs is really this slow.

Old 01-14-2004, 07:16 PM   #2
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bump - just making sure everyone's seen it that might be working better than me.
Old 01-16-2004, 01:28 AM   #3
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As I understand it, NFS requires syncronous writes (this was the original specification so I don't know if it's changed in the last several years). That means the NFS server has to wait until it's confirmed that the data is written to disk before it can return the message to the client that the data has been written. That will provide overhead regardless of how fast the disk is that you're writing to, or whether you're NFS server kernel is using a journaling file system. That being said, using faster disks and fs journaling on the server will certainly help.

By the way, 10MBytes/s is a pretty freakin good transfer rate. You can never reach the rated maximum bandwidth of a network any way because of protocol overhead, other stray traffic, time to transfer the data out of buffers, etc...
Old 01-16-2004, 03:39 AM   #4
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i get 28.791 on the write (to a 120MB WD SE drive on a PII350) and 13.383 on the read (to my fast computer). i notice gkrellm shows occasional peaks (approx 2/sec) on eth1 at around 40MB/s and the read/write is limited by hd IO. judging by the relative areas of the gkrellm outut, no ethernet traffic exists for ~90% of the transfer test. i'm testing gigabit cards (intel pro 1000) talking through a 10m CAT-6 cable. since you have a switch in the line, i wonder what your nics peak at when it actually sends packets?

Last edited by bdp; 01-16-2004 at 03:45 AM.
Old 02-03-2004, 01:24 PM   #5
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nevermind. guess it's too late to delete this post.

Last edited by BrianK; 02-03-2004 at 07:29 PM.


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