[rescue] Q: OpenVMS NFS performance questions7

[Eric Dittman]

> > > So, what do people think is the best OS for NFS serving?  A few years, I
> > > got the impression that studios tended to think that Solaris was the
> > > best (mainly since apparently it didn't crash as much, or cause the
> > > clients to crash as much).  I'm quite certain from my own experience
> > > that Linux and NT aren't the best.  One of these days I want to try and
> > > rigorously compare NetBSD and Solaris 8 against each other on an
> > > Ultra1.  It is pretty high on my list of things to do once I graduate
> > > since replacing an old P75 running linux as a file server is a high
> > > priority.
> >
> > I recommended *BSD since it will run on the Alpha he has and
> > won't cost anything.
> 
> You seem to be talking at cross purposes.  Francisco wanted to see why NFS
> performance was poor on OpenVMS/Alpha, and Joshua wanted to determine the
> ideal NFS serving platform for his network.  Two separate issues.

NFS serving on OpenVMS won't be as good as Unix.  I also
notice that generally FTP transfers aren't as fast, either,
but part of this also depends on which TCPIP software is
loaded.

> Francisco, OpenVMS NFS performance probably isn't the best, but it should
> be fairly close to most Unix implementations.  With speeds like you've
> mentioned I would suspect a fundamental networking problem such as severe
> packet loss or a duplex mismatch.  Can you transfer a large file via FTP
> in a reasonable amount of time?

I agree that checking the speed via FTP is a good test.  Also,
the first version of the DE500 did not autonegotiate, so if
the SRM setting isn't correct and the switch doesn't properly
negotiate there will be problems.

The settings for the card can be checked under OpenVMS with LANCP.

One issue we recently experienced on an 8400 with a DE450 was due
to using HDX.  The DE450 and the switch were both configured for
HDX, but after about five minutes into an FTP transfer late collision
would increase.  This resulted in either a timeout or extremely long
transfer time.  Changing the DE450 and switch to FDX solved that
problem.

> My recent experience with OpenBSD and NetBSD shows them to drag behind
> Solaris in performance, though they all seem to be substantially ahead of
> Linux for protocol conformity.  Client architecture plays a role as well,
> you will see significantly better performance with a Solaris client and a
> Solaris server than with mismatched clients due to proper NFSv3 support.
> TCP vs UDP is another discussion entirely, which one is appropriate
> depends almost entirely on your network architecture and loading.

The last time I tried using Linux as an NFS server the speed was
terrible.  I've heard things have improved, but I haven't tried
lately.

> For what it's worth, I see 90%+ of 100mbps wire speed on large transfers
> between Solaris/Solaris, and io tps tracks disk seek time to within 25%
> for synchronous operations serving off of a single noncached disk.  That's
> good enough for me.

I've seen good results with Solaris as well.
-- 
Eric Dittman
dittman at dittman.net
Check out the DEC Enthusiasts Club at http://www.dittman.net/