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] streaming server on a virtual machine.

To: "Fajar A. Nugraha" <fajar@xxxxxxxxx>
Subject: Re: [Xen-users] streaming server on a virtual machine.
From: Grant McWilliams <grantmasterflash@xxxxxxxxx>
Date: Sun, 27 Sep 2009 07:25:39 -0700
Cc: xen-users <xen-users@xxxxxxxxxxxxxxxxxxx>, Mauro <mrsanna1@xxxxxxxxx>
Delivery-date: Sun, 27 Sep 2009 07:26:41 -0700
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :from:date:message-id:subject:to:cc:content-type; bh=iOQxOeK/AGEPokAnpKTg2XJe2egNQDs6oO737OhRXc0=; b=Lq49+F5djwIH6++CFAIff1ljD2TTlF+yjGYK2wbqwN9EMuKPB2tXVMwfCG1xk2Zn5O Z9z8whtXDVsleOKzH4Xw0+XWV/ThVSVlqKVhXurO0MQcmUNMrrPbtrCN0orlJ1LD3JDZ QeoiUFIPBKBaehnLPn34FvIcakoCiH0/HFUDA=
Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; b=XiDNUsVC47iqqI4+1o6P6zrcpVb2oBDNJ5geL+jk6aDkAUyzesAdh4LiwdUe/6e+RQ Gxj4Hq95v1kvBgs1R7ubPUX0HJvxgwpWg8kfrZUYLY19CUDIT7arQuN134iSnK/RGOpM J0sTe+ylBD4DFa9GdNi5H5oQoU2kt8Oq47yFU=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <7207d96f0909261128w1754d31p7f7917bebd8c05f6@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: <ab520d140909180307g31d6c768i8a749509a066354b@xxxxxxxxxxxxxx> <64D0546C5EBBD147B75DE133D798665F03F3EA79@xxxxxxxxxxxxxxxxx> <ab520d140909260242n1e50914cvba5bc5bc0e510701@xxxxxxxxxxxxxx> <ed123fa30909260705m550ea320o2f721d129e13cdca@xxxxxxxxxxxxxx> <ab520d140909261056w37f824dbybca94cbc2a10bdf8@xxxxxxxxxxxxxx> <7207d96f0909261128w1754d31p7f7917bebd8c05f6@xxxxxxxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
On Sat, Sep 26, 2009 at 11:28 AM, Fajar A. Nugraha <fajar@xxxxxxxxx> wrote:
On Sun, Sep 27, 2009 at 12:56 AM, Mauro <mrsanna1@xxxxxxxxx> wrote:
> 2009/9/26 Grant McWilliams <grantmasterflash@xxxxxxxxx>:
>> I will also add that if Xen has a bottleneck it's traffic between DomUs.
>> Don't configure it in any way to have
>> one DomU servicing another DomU unless both have real  network cards
>> attached to them.

> Thank you for your answer it was very exhaustive.
> I've learned a new thing, that is the poor performance in traffic
> between domU in the same machine rather than domU in different
> machines.
> I've a domU with tomcat and many jruby applications and, in the same
> machine, another domU as database server with postgres.
> Based on what you say I've to reconfigure my systems to have domU in
> different machines.

Were you having network performance problems?
There was a thread on this list some time ago about domU <-> domU
network performance, and the ones that experience it were using newer
pv_ops kernels while people who use 2.6.18 kernel (like RHEL/Centos5)
or Suse -xen kernel got good performance.


Instead of having a second physical server just to get decent
performance, I'd say it's easier to simply change your dom0 kernel.


The domU to domU performance problem that I extensively tested and documented was with the 2.6.18 without pv_ops.
The problem does not appear if the traffic is routed straight out of the box. I saw full GB speeds from a DomU to any other machine.
I'd get about 350-400 Mb/s between DomUs. After changing every variable and digging through the xen-users and xen-devel archives
the answer I got was yes, that does exist and the solution was to assign a NIC to the domU or only have DomUs communicate with DomUs on
other physical machines. This was with Xen 3.2.1. I haven't rerun my testing with 3.4 yet because I worked around it.

Grant McWilliams

Xen-users mailing list