default nfs mount options from linux to linux

Does anyone know what or how to find the default mount option are when mounting an nfs volume?
example
mount linuxnfs:/export /mnt

How do I find the rsize/wsize and any other options? (that are default)

I am lead to believe that the nfs man page information is false for r/wsize 1k (no way) (udp default is correct though). If I set the r/wsize to 1k performance is very slow. In a "vanilla" default as above it has the fastest iozone benchmarks.

Thanks,
-Brad

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If you want to empirically determine a good wsize, for example, you might try the script below. I still haven't had a chance to use it, but I'd like to think it'll work fine. :)

Also, if you're on a gigabit network, you may be able to improve NFS performance a lot by turning on jumbo frames.

#!/usr/local/bin/bash

# with these options:
# bg,hard,intr,rsize=8192,wsize=8192
# we got 50Mbps over NFS to ext3 from esmf04d to esmft2
# I suspect UDP may be faster; we're using tcp here.  Not sure why AIX
# isn't reporting that.

#mount -o vers=3,proto=tcp,rsize=8192,wsize=8192 esmft2:/foo /mnt/foo for proto in tcp udp
do
for vers in 3 2
do
for size in $(seq 1024 16 65536)
do
echo
echo $vers $proto $size
cd /
umount /mnt/foo
mount -o insecure,vers="$vers",proto="$proto",rsize=
$size,wsize=$size \
esmft2:/foo /mnt/foo
cd /mnt/foo
rm -f testfile
# write 10 gigabytes
echo writing 10 gigabytes: $proto $vers $size /bin/time dd if=/dev/zero of=testfile bs=1024k count=10240 2>&1
done
done
done

Mount the volume without options and check /proc/mounts. Note that some options may differ based on negotiation with the server.

Regards,
---
Bruce Allan <[email protected]>
Software Engineer, Linux Technology Center
IBM Corporation, Beaverton OR USA
503-578-4187 IBM Tie-line 775-4187

Bradford Arrington <[email protected]>
Sent by: [email protected]
04/21/2005 06:01 PM

To
[email protected]
cc

Subject
[NFS] default nfs mount options from linux to linux

Does anyone know what or how to find the default mount option are when mounting an nfs volume?
example
mount linuxnfs:/export /mnt

How do I find the rsize/wsize and any other options? (that are default)

I am lead to believe that the nfs man page information is false for r/wsize 1k (no way) (udp default is correct though). If I set the r/wsize to 1k performance is very slow. In a "vanilla" default as above it has the fastest iozone benchmarks.

Thanks,
-Brad

-------------------------------------------------------
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_______________________________________________
NFS maillist - [email protected]
https://lists.sourceforge.net/lists/listinfo/nfs

-------------------------------------------------------
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_______________________________________________
NFS maillist - [email protected]
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Bruce,

First thank you to all who replied.

It turns out I should have just looked at the source code to the mount command found in utils-linux tar package.

It seems that although it may look like its mount with 8k r/wsize, the mount C code says it is automatically changed by the kernel it self when needed.

This explains a lot because if I where to just mount it with 8k r/wsizes the performance is slower than if I where to just mount linux to linux with out any options (i.e. mount linxnfs:/export /mnt). These seem to be the initial defaults :
nfs rw,v3,rsize=8192,wsize=8192,hard,udp,lock

However this does not work with Solaris 10, in order to get higher throughput speeds you must specify 8k r/wsizes

-Brad

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_______________________________________________
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You can generally verify the actual rsize/wsize using a sniffer, like ethereal, tcpdump -v or snoop.

Solaris should be defaulting to 8K rsize and wsize, as should almost all unixes. It's the linuxes that have historically used smaller rsize/wsize - I'm led to believe this was because so many network cards used with linux used to be poor, and liked having smaller NFS blocksizes.