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Re: [Xen-devel] Shouldn't backend devices for VMX domain disks be opened

To: Anthony Liguori <aliguori@xxxxxxxxxx>
Subject: Re: [Xen-devel] Shouldn't backend devices for VMX domain disks be opened with O_DIRECT?
From: Rik van Riel <riel@xxxxxxxxxx>
Date: Thu, 2 Feb 2006 21:40:33 -0500 (EST)
Cc: Steve Dobbelstein <steved@xxxxxxxxxx>, "Philip R. Auld" <pauld@xxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
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On Thu, 2 Feb 2006, Anthony Liguori wrote:

> Referring to the original question, which has been quoted away, 
> journaling doesn't require that data be written to disk per-say but that 
> writes occur in a particular order.  A journal is always recoverable 
> given that writes occur in the expected order.

If I do a database transaction or accept an email (SMTP transaction),
I need to ensure that the data really did make it to disk.

There is a reason that the email RFCs explicitly state that the email
has to be committed to stable storage before returning the "250 Ok"!

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