[ale] Fast NFS

[Stephan Uphoff]

On Sun, 2004-09-12 at 13:52, Bob Toxen wrote:
> On Sat, Sep 11, 2004 at 05:12:28PM -0400, Christopher Fowler wrote:
> > Is tehre a way I can make sure my NFS server provides my clients top
> > priority?  I'm using an ARM board and am nfs rooting it.  Every so often
> > during heavy use I get nfs server not responding errors.  I need to
> > place swap over NFS and so I do not need the kernel barfing.
> 
> As others have noted:
> 
>   1. Use UDP instead of TCP for performance but recognize that
>      there is no security in this route and thus it is critical
>      that NFS be used only on a private network with a *good*
>      firewall in front.
> 
>   2. It appears that there is a memory problem, though if you're
>      swapping across the network ...
> 
> Try mounting with the following options:
> 
>   async
>   rsize=8192,wsize=8192
>   udp
>   timeout=x (try x of 100)
> 
> I disagree with the other poster that a small rsize and wsize will
> improve the situation.  My analysis shows just the opposite.

Every now and then I see fragmentation issues as described in
 	http://citeseer.ist.psu.edu/kent87fragmentation.html

Just because a NIC or switch is 100 MBit does not mean that
it can handle 10 packets back to back with this speed.

I agree - performance with small packets is bad - but sometimes
it is the only way that works. (Or using TCP)

However it looks like he is lucky and just needs to tune his VM.

> 
> Bob Toxen
> bob at verysecurelinux.com               [Please use for email to me]
> http://www.verysecurelinux.com        [Network&Linux/Unix security consulting]
> http://www.realworldlinuxsecurity.com [My book:"Real World Linux Security 2/e"]
> Quality Linux & UNIX security and SysAdmin & software consulting since 1990.
> 
> "Microsoft: Unsafe at any clock speed!"
>    -- Bob Toxen 10/03/2002
> 
> --===============0825835916==--
> 
> 
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://www.ale.org/mailman/listinfo/ale
> 
>