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Date: Tue, 3 May 2011 08:55:15 +0200
Message-ID: <BANLkTinqn6=UJdF3H+seTskuk5JRtW9-kg@mail.gmail.com>
Subject: Re: How does NFS handle notify?
From: Stef Bon <stefbon@gmail.com>
To: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>, linux-nfs@vger.kernel.org
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Sender: linux-nfs-owner@vger.kernel.org
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2011/5/3 Trond Myklebust <Trond.Myklebust@netapp.com>:

> You've proposed a 'solution', but I'm still not seeing what the problem
> is.
>
>     1. Why do we need to develop kernel support for dnotify+inotify+...
>        in every networked filesystem + fuse?

Well yes that's a problem indeed. I see also there are more different
types, which do not make life easier.

>     2. What are the killer app use cases that we need to support and
>        that cannot be supported with existing methods?
>

I do not have one, only the idea that Linux in general will benefit,
when notify is supported for users using cifs, nfs and fuse fs's like
mine.

> Notifications on large distributed filesystems are a scalability
> nightmare (particularly so for inotify), so they need careful
> justification and need to be limited in scope. Just pulling out a
> solution from your magic hat isn't sufficient.

I do not have much experience with large distributed filesystems (can
you name an example?) but isn't it possible to just turn notify off
for such systems?

Stef