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RE: [Xen-users] Should applications be running on Dom0

To: "Nathan Eisenberg" <nathan@xxxxxxxxxxxxxxxx>, <Xen-users@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-users] Should applications be running on Dom0
From: Jeff Sturm <jeff.sturm@xxxxxxxxxx>
Date: Wed, 18 Aug 2010 19:12:21 -0400
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Thread-topic: [Xen-users] Should applications be running on Dom0

I have two reasons, neither based on theory, but pragmatism.

 

One is to keep dom0 stable.  A domU crash, due to a badly behaved application (i.e. OOM) can be handled easily with "xm destroy" if nothing else works.  There is no "xm destroy" for dom0, and a dom0 recovery sometimes involves switching power to the physical host.   (Losing all guests in the process.)

 

Another is simply to give as much memory to the guests as possible.  We run many applications that benefit from disk caching or application buffers, both of which are limited to the memory assigned to the domU.  The dom0 on the other hand can run efficiently in a very small memory footprint (512MB or less).

 

From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Nathan Eisenberg
Sent: Tuesday, August 17, 2010 3:47 PM
To: Xen-users@xxxxxxxxxxxxxxxxxxx
Subject: RE: [Xen-users] Should applications be running on Dom0

 

I hear this often, but I have yet to hear a satisfactory and technical explanation as to why.  I’m not sure I agree that it is true.

 

Why is this the case?

 

-Nathan

 

From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Jonathan Tripathy
Sent: Tuesday, August 17, 2010 12:35 PM
To: Brent Bolin; Xen-users@xxxxxxxxxxxxxxxxxxx
Subject: RE: [Xen-users] Should applications be running on Dom0

 

Depends on what your Xen setup is being used for.

 

If it's strictly lab/testing/internal things, then it really doesn't matter

 

If you're hosting stuff to the outside world, then the only thing that should be running on the Dom0 (apart from the Xen Guests), is iptables to firewall the guests.

 


From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx on behalf of Brent Bolin
Sent: Tue 17/08/2010 20:27
To: Xen-users
Subject: [Xen-users] Should applications be running on Dom0

Or should Dom0 be lightweight with guest o/s's be doing that?

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