This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-users] Measure disk activity in full-virtualization.

To: deshantm@xxxxxxxxx
Subject: Re: [Xen-users] Measure disk activity in full-virtualization.
From: "Alain Barthe" <ab266061@xxxxxxxxx>
Date: Mon, 21 Jul 2008 11:21:23 +0200
Cc: Alejandro Paredes <aleparedes@xxxxxxxxx>, xen-users@xxxxxxxxxxxxxxxxxxx
Delivery-date: Mon, 21 Jul 2008 02:22:04 -0700
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type:references; bh=KX8R3+i8joOgKlO5/wAQQI3YbR7ZLozGYF4l2hSr4cA=; b=WWEpyX1c+4/fwD6V2FM2JN+A7Cue5JcRGL+5LBctbP9xPfwUunzl7FFqzv5fRKao8Y xUJbqagiYbSS3p0QgfthFQOlm3/SjkSX8k9QbgJhsI6L4hx6vRfwz7ArlRSTDWWIUstf QOGuZRjR9QBQZUHHugG+PYYpIwlgMiaQDFoF8=
Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:references; b=EibM9BP8d1yFDBcOP1ck+AW5XU3KaLeRTsb46KN+1owR1wo3FRHovhkr2EcuhBEyTs +OKV2McVJdKJ6A/NpqERLZ5PA3/CqgGupV6oQhA5BH/Gw//cIn0sxOfjHd3DYaQhkq8u lQA52QZRUdsseZU9eCwuDhNQPf4QJ3MmyXJCw=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <1e16a9ed0807191909u7b0cca5j98883564886013b2@xxxxxxxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References: <c8c57fc50807181230lf19cd2dmfef3db9eb92c1881@xxxxxxxxxxxxxx> <1e16a9ed0807191909u7b0cca5j98883564886013b2@xxxxxxxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
2008/7/20 Todd Deshane <deshantm@xxxxxxxxx>:
Are you familiar with the work at Clarkson University regarding performance isolation?


I am very surprised by this publication whose conclusion is that a full virtualised environment (VMWare) provides a perfect isolation between VMs while a para virtualised one (Xen) is good but not perfect.

Our experience concerns WMWare server and Xen, we done some subjective and practical tests (measuring the time some real huge tasks take to acheive) and listen to users complains, and the results were quite clear : on VMWare server, when a VM is very busy, its process eats all the CPU it runs on, and other VMs slow down significantly along with the host itself. When the number of VCPU exceeds the number of CPU (it is the general case), you may have a delay of several second to see the echo of the character you typed on a VM that does nothing because another one on the same host is 100% busy.

With Xen, no such a behaviour, isolation looks like much better. That why we migrated all our servers from VMWare to Xen.

Perhaps benchmarks don't always reflect the real world...

Xen-users mailing list

Xen-users mailing list