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Re: [Xen-devel] [PATCH 0 of 2] [Resend v2] remus: Checkpoint Compression

To: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH 0 of 2] [Resend v2] remus: Checkpoint Compression
From: Shriram Rajagopalan <rshriram@xxxxxxxxx>
Date: Wed, 22 Jun 2011 12:47:48 -0400
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
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On Wed, Jun 22, 2011 at 4:23 AM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
On Sun, 2011-06-19 at 05:32 +0100, Shriram Rajagopalan wrote:
> This patch series adds checkpoint compression functionality to Remus.

Would there be any benefit to applying this technique to the second and
subsequent rounds of a normal live migration? Or do you need the greater
number of rounds which Remus implies to really see the benefit?

The benefits (bandwidth wise) will show up from 3rd round or so. 1st round, since
"all" pages are sent as-is, they are not cached. 2nd round is where you would
start caching pages. 3rd round onwards, you would see the benefits of the compression
(depending on the workload in the VM).

It all really depends on the workload, network state (lan vs wan) at the time of live
migration. I havent really played around with live migration+compression combo,
to give you a definitive yes/no.


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