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RE: [Xen-users] best way to optimize use of CPU and IO

To: "Itamar - IspBrasil" <itamar@xxxxxxxxxxxxxxxx>, "Fong Vang" <sudoyang@xxxxxxxxx>
Subject: RE: [Xen-users] best way to optimize use of CPU and IO
From: "Ross S. W. Walker" <rwalker@xxxxxxxxxxxxx>
Date: Thu, 24 Apr 2008 22:51:43 -0400
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Thread-topic: [Xen-users] best way to optimize use of CPU and IO
Itamar - IspBrasil wrote:
> Fong Vang wrote:
> > I have a system with 2 quad core CPUs running Xen on CentOS 5.1 
> > 64-bit.  The kernel sees this system as having 8 CPUs.  If I were to 
> > create 6 domUs, what would be the best way to allocate the CPUs to get 
> > best CPU and IO performance?  Should all CPUs be allocated to all domU 
> > and let the system allocate as it sees fit or would the system perform 
> > better if each domU is restricted to fewer CPUs?
> >
> > Each domU is running a custom Java application that utilizes MySQL 
> > heavily.  Application is heavily threaded.
> put mysql on another machine.

I do not understand how you can blindly say that. You don't know the type
of CPUs, the amount of memory, or the type of storage the OP is using, so
there is no qualification to say that.


If anything, in the end it will probably be the Java engine that may
need it's own sandbox to play in. You could setup 8 separate MySQL
read instances and load balance well under Xen. Java... well that's
another story.

You need to allocate the number of CPUs based on the application and how
your processors react to the Xen scheduler.


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