Re: very poor nfs performance

[Dan Ritter <dsr@randomstring.org>]

Mike Kupfer wrote: 
> Stefan K wrote:
> 
> > > Can you partition the files into 2 different shares?  Put the database
> > > files in one share and access them using "sync", and put the rest of the
> > > files in a different share, with no "sync"?
> > this could be a solution, but I want to understand why is it so slow and fix that
> 
> It's inherent in how sync works.  Over-the-wire calls are expensive.
> NFS implementations try to get acceptable performance by extensive
> caching, using asynchronous operations when possible, and by issuing a
> smaller number of large RPCs (rather than a larger number of small
> RPCs).  The sync option defeats all of those mechanisms.

It is also the case that databases absolutely need sync to work
properly, so running them over NFS is a bad idea. At most, a
sqlite DB can be OK -- because sqlite is single user.

-dsr-