2007-11-30 16:31:20

by Wendy Cheng

[permalink] [raw]
Subject: Re: [NFS] NFS Digest, Vol 18, Issue 70 (NFS performance problems)

Trond Myklebust wrote:
> Actually, the real problem would be dealing with something like
> unlink('foo') followed by open('foo', O_CREAT|O_EXCL). How do you ensure
> that a replay of those actions following a reboot is fully consistent in
> the face of some other client attempting an open('foo', O_CREAT) at the
> same time?
>
> The problem is that a number of directory operations involve exclusive
> semantics, and so cannot be replayed. The solution to this sort of
> problem is going to have to involve exclusive (i.e. write) directory
> delegations to ensure that whatever transactions one client performs
> cannot interfere with the transactions performed by another.
>
>

Well, a dumb question from me (borrowing Bruce's line :) ) ... even with
"sync" in place, when server rebooted, the RPC reply cache is gone. How
does linux server handle re-transmitted non-idempotent requests ?

-- Wendy



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