Re: nfs server performance (netbsd-5)

[Matthias Scheler <tron%zhadum.org.uk@localhost>]

On Tue, Apr 27, 2010 at 10:51:16PM +0000, Christos Zoulas wrote:
> >3.) I proposed a Google Summer of Code project to get this fixed:
> >
> >     http://mail-index.netbsd.org/tech-net/2010/04/06/msg002004.html
> 
> Solution 2 does not work because there are always race conditions
> when you mount and access things from userland.

Why would that happen? The puffs file-system can surely block all
requests to the same path while it is mounting a remove
file-system on it.

> The automounter is a userspace application already;

I know, I mention that in my proposal.

> ... it pretends to be an NFS server for all the "auto" directories it
> manages ...

Yes, and using NFS causes IMHO a lot unnecessary overhead. puffs should
be much more efficient because it e.g. doesn't have to encode all
actions via RPC.

> The problem is that it forks in order to do things in parallel and non
> blocking form, and one child can race with another child undoing what
> the first child does.

Well, that sounds like an implementation problem rather like a
fundamental issue.

        Kind regards

-- 
Matthias Scheler                                  http://zhadum.org.uk/