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From: PANKAJ RAWAT <pankajr141@gmail.com>
To: qemu-devel <qemu-devel@nongnu.org>
Subject: [Qemu-devel] I/O in backing file
Date: Wed, 28 Mar 2012 10:47:08 +0530	[thread overview]
Message-ID: <CABZruFABhGLdUKDTj4MsjDAUoyHy=S7bm1Xfu7MeNSkRkv+fDw@mail.gmail.com> (raw)

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Hi all,

I am currently using backing file.The question of my concern is regarding
the I/O operation
Now when we create a external snapshot in qcow2, a new file is created
leaving the original file as backing file
*
Can any one tell,*how the I/O is performed in detail way?.

Means when the new snapshot is booted which refer to the backing file as
original file. *How read operation is performed? how it is decided whether
the file is present in the snapshot image or the backing file.?
when write operation is performed how it is decided whether the file is
already present in backing file or we have to create a new one ?*

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             reply	other threads:[~2012-03-28  5:17 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-28  5:17 PANKAJ RAWAT [this message]
2012-03-30  4:17 ` [Qemu-devel] I/O in backing file PANKAJ RAWAT
2012-03-30  7:07   ` Stefan Hajnoczi

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