I have all my iTunes data on a linux NFS server, which I had previously used with a Windows box via Samba. The new iMac uses NFS to access the same data store. I found changing ID3 tags to be very, very slow compared to the Windows box. It turns out that write performance seriously lagged. smb_fs mounts performed well, but could not be automounted, so I ended up tuning the NFS settings.
The critical factor that affected performance was the number of nfsiod threads. Adding more threads means that more simultaneous NFS operations can occur at once (including read-ahead and write-behind operations). To increase this value, simply edit the file /System -> Library -> StartupItems -> NFS -> NFS, and change the line that reads:
nfsiod -n 4Replace the 4 with 8 or more, followed by rebooting or manually killing and re-running nfsiod. You will notice an increase in throughput when writing large files. To test the speed, run the following command before and after the change:
time dd if=/dev/zero of=/mnt/home/testfile bs=16k count=16384Going from 4 to 8 nfsiod threads resulted in write speeds going from 700k/sec to over 3.2mb/sec! Further tuning can be found by reading the Linux NFS How-To Performance Section.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030504042711312