[CentOS] Centos 5.2 and Xen

[Luke S Crawford]

Tom Lanyon <tom at netspot.com.au> writes:
> I haven't been following the thread, but has the discussion been about
> memory limits of Xen?

We were discussing memory limits of the free (as in beer) closed source 
citrix xensource product-  limits are added to the free product in order
to encourage people to upgrade to the more expensive products.  

These limits don't exist in the open-source xen product, which is what
the centos/Xen stuff is based on.

http://tx.downloads.xensource.com/downloads/docs/user/#SECTION01130000000000000000

> Am I going to face any issues wanting to run some CentOS 5.x x86_64
> boxes with 16 or 32 GB memory as Xen hosts with up to 10 or 12 GB
> memory CentOS 5.x x86_64 domUs ?

I've personally run CentOS x86_64 5.1 boxes with north of 16G ram- 
there is nothing I am aware of that would stop you from putting as much 
ram as you want in a particular DomU.  

> Furthermore, am I going to encounter issues running CentOS 5.x i386
> boxes with 8 GB memory trying to run CentOS 4.x i386 domUs with 3.5 or
> 4GB memory?

You will be needing PAE, but that is default for CentOS i386/xen, so it
should Just Work.  make sure you install the libc6-xen package (should
be installed as a dependency.)  The usual PAE limits apply.  

I'm typing this message in emacs running on a DomU hosted on an i386/PAE box 
with 6G ram running CentOS5.1/xen.