[CentOS] Centos 5.2 and Xen

Ruslan Sivak russ at vshift.com
Thu Jun 12 01:46:17 UTC 2008

Luke S Crawford wrote:
>> I wonder if it can be combined with other technologies - KVM, openVZ, etc to give more then 4GB of ram for virtualization?  I tried installing vmware, but it wouldn't run under.a xen kernel.  
> running vmware under a xenU guest wouldn't lift any ram limit imposed by the 
> xen kernel or dom0.
> the 4Gb limit is added to the free (closed source) citrix xen product
> so that people have a reason to pay for the full version...  really,
> if you need more than 4G, pay for full xensource, or use the open-source
> Xen/open source pv drivers.
The 4GB limit is artificial, and only applies to the vm's started using 
their closed source XenSource.  The host OS is most likely CentOS 5, and 
sees the whole 8GB (although it's not x64, so I'm guessing they use PAE 
or something.)

I only need 8GB of ram support, and no other features that are offered 
in XenStandard, so it seems kind of a waste to pay $1k per server for 

If another virtualization technology was installed on that OS, you can 
get the use of the other 4GB, and if not, I can always run my apps on 
Dom0, although I'd prefer to not install too much stuff on Dom0.


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