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Date: Mon, 24 Apr 2006 20:13:56 -0700 (PDT)
From: Mohan Srinivasan <mohan_srinivasan@yahoo.com>
To: Sam Leffler <sam@errno.com>, Kris Kennaway <kris@obsecurity.org>
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Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org,
	Mohan Srinivasan <mohans@FreeBSD.org>
Subject: Re: cvs commit: src/sys/nfsserver nfsrvcache.h
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--- Sam Leffler <sam@errno.com> wrote:

> > 
> > Fundamentally it doesn't, this change just pushes it out of the regime
> > where it's trivial to overflow.
> 
> Why is it hard to do a real fix?  Or is this a temporary bandaid?

Most NFS server that I am aware of will scale the duplicate request cache
based on the memory available (and we should probably do the same).

It is very easy to overflow a 64 entry duplicate request cache though, and
bumping it makes sense.

So, this is not a bandaid. The real fix is to use NFS/TCP, although even 
there, the duplicate request cache cannot be completely eliminated, because a 
non-idempotent request can be re-transmitted after a connection teardown
and re-establishment.

mohan