Bad performance while transfer large block size through NFS.

Claus Guttesen kometen at
Fri Jun 1 11:27:26 UTC 2007

> I set up one NFS server, and mounted on other server by TCP. Servers
> connected with Giga network, and running 6.2-RELEASE.
> But I found the performance is very bad while transfering large block size data.
> For example, I use dd on NFS client to test the speed.
> And ``systat -vm 1'' is displayed HDD is most busy,
> Disks   da0
> KB/t  16.00
> tps     239
> MB/s   3.73
> % busy   91
> Can I do some tuning to improve large block size transfer over NFS?

Try adding read- and write-size 32768, partial /etc/fstab:


or adding -r 32768 -w 32768 while mounting from command line.


When lenity and cruelty play for a kingdom,
the gentlest gamester is the soonest winner.


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