NFS installation

So I decided to put an NFS server to my DreamPlug. First, an easy step:

apt-get --no-install-recommends install nfs-kernel-server

Let's see what do I have:

root@plugged:~# lsmod | grep nfs

nfsd                  243695  11 
exportfs                3108  1 nfsd

So, next step is to export a directory. I would like to create a read-only export.

cat /etc/exports

/mnt/md2        192.168.0.2(ro,no_subtree_check)

TODO: Some security Okay, so let's restart the nfs server:

/etc/init.d/nfs-kernel-server stop
/etc/init.d/nfs-kernel-server start

Install the client on the other machine:

sudo apt-get --no-install-recommends install nfs-common

And mount the export:

sudo mount 192.168.0.4:/mnt/md2 /mnt/md2

It does not seem to perform very well. For example, from the client, through wifi:

time ls -la /mnt/md2/1/ > /dev/null

Gives

real 1m18.605s
user 0m0.560s
sys 0m2.632s

Whereas running the same stuff on the DreamPlug:

real 0m2.572s
user 0m1.650s
sys 0m0.920s

And that's fast. Let's try to dd some files.

dd if=/mnt/md2/1/ffc4f5bc7f6b78ac371f3ecebdd9701e4cb8c68f of=/dev/null

Gives:

577409024 bytes (577 MB) copied, 103.255 s, 5.6 MB/s

And what is the raw speed? On the server:

nc -l -p 4545 -q 1 < /mnt/md2/1/ffc4f5bc7f6b78ac371f3ecebdd9701e4cb8c68f

On the client:

nc 192.168.0.4 4545 | dd of=/dev/null

And the results:

577409024 bytes (577 MB) copied, 103.84 s, 5.6 MB/s

So nfs gives almost no overhead. (Please note, that the 1 sec was the waiting time added by the netcat server. That's negligable.) Let's see the same thing locally on the server:

dd if=/mnt/md2/1/ffc4f5bc7f6b78ac371f3ecebdd9701e4cb8c68f of=/dev/null

Result:

577409024 bytes (577 MB) copied, 19.4105 s, 29.7 MB/s

NFS over a gigabit connection (after umount-mount, to clear the cache):

577409024 bytes (577 MB) copied, 24.6491 s, 23.4 MB/s

Without NFS (nc way):

577409024 bytes (577 MB) copied, 20.9865 s, 27.5 MB/s

So yes, NFS has some overhead at these rates.