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[Xen-users] Sharing a partition between dom0 and domU

To: Xen Users Mailing List <xen-users@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-users] Sharing a partition between dom0 and domU
From: Marcin Owsiany <porridge@xxxxxxxx>
Date: Thu, 15 Dec 2005 19:13:27 +0100
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I'm currently preparing to xen installation. In the system that I'm
going to set up, there will be a need to copy large amounts of data
(therefore I want to avoid using network) from domUs to the dom0 (one
way only).

Mounting a filesystem RO, when a domU has it mounted RW is probably
asking for trouble. Therefore I was thinking about using some remounting
protocol similar to what's described in thread starting at

But then I thought about making LVM snapshots of the domU partition, and
mounting it RO in dom0. Has anyone tried this?

What I'm worried about is that the snapshot would have to be taken in an
instant at which the filesystem is in a consistent state. IIRC the
kernel enforces consistency when one is using LVM in a single system, by
telling the filesystem driver to make the filesystem consistent for the
moment the snapshot is being taken. But I'm not sure how to tell the
kernel in domU that dom0 is about to take a snapshot of its filesystem.

Please note that I have no desire to _completly_ eliminate network
usage. Using it for some kind of synchronization between the domains is
fine with me. I just want to avoid copying the large data across the

Any ideas?


Marcin Owsiany

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