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  • Writer's picturekyle Hailey

NFS throughput testing trick (solaris)

When testing the read and write speed to an NFS mounted file system it’s often unclear if the bottleneck is the speed of the network connection or the speed of the underlying storage. For the underlying storage it would be nice just take it out of the equation and concentrate on the network speed. For network speed testing for NFS mount here is a cool trick to take the storage subsystem out of the equation by using a ramdisk. On the NFS server create a ramdisk

ramdiskadm -a ramdisk1 1000m
newfs /dev/rramdisk/ramdisk1
mkdir /ramdisk
mount /dev/ramdisk/ramdisk1 /ramdisk
share -F nfs -o rw /ramdisk
chmod 777 /ramdisk

Then on the NFS client, for example LINUX, mount the ramdisk

mkdir /ramdisk
mount -t nfs  -o  'rw,bg,hard,nointr,rsize=1048576,wsize=1048576,tcp,nfsvers=3,timeo=600'   192.168.1.1:/ramdisk /home/odbadmin/ramdisk

Now, on the target I can read and write to the ramdisk and avoid the disk speed issues:

time  dd if=/ramdisk/toto of=/dev/null bs=1024k count=800
838860800 bytes (839 MB) copied, 7.74495 seconds, 108 MB/s

For read tests, be aware that in many cases, reads will come from caching on the client side after the first run.

And to drop the ramdisk

 umount /ramdisk
 ramdiskadm -d ramdisk1
 

UPDATE: thanks to Adam Leventhal for this tidbit. Instead of creating a ramdisk, just use /tmp:

On Server

 share -F nfs -o rw /tmp

On client:

mkdir /tmpnfs
mount -o vers=4,rsize=32768,wsize=32768 172.16.1.1:/tmp  /tmpnfs
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