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Can xen server be configured to address more than 4Gb RAM. Since its based on a 32 bit kernel,is it possible to address more than 4GB ram.I have heard about PAE can it solve this?

Will changing the default 750M to more than 4Gb results in any performance degradation?

The only reason i want to add more ram to host is to load a 5 GB VM to completely run on RAM,for maximum performance benefits,for some testing purpose.

Installed RAM is more than 64 GB,and a lot of unused RAM.

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why not just use a 64bit Xen server? – Chida Aug 19 '12 at 15:28
using Xen Cloud Platform!!which is based on 32 bit centos kernel,and xen server 5 – Blue Gene Aug 19 '12 at 15:34
XCP can support 64bit. It's much much easier if you use 64bit XCP and you can utilize ALL of your 64GB and even add more RAM if you need. – Chida Aug 19 '12 at 15:40
up vote 1 down vote accepted

With a 3-2bit System, every application can address up to 4GB of memory. PAE only lets you put more RAM in the Server to let more applications run with their 4GB.

If you really need to address more then 4GB you have to switch to a 64-bit kernel.


This document suggests that Xen Cloud Platform is based on a 64-bit system:

The Xen Cloud Platform host is a 64-bit x86 server-class machine devoted to hosting mul-tiple VMs. This machine runs a stripped-down Linux operating system with a Xen-enabled kernel which controls the interaction between the virtualized devices seen by VMs and the physical hardware.

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In the host machine i dont need to run any application,all the applications are on VMs.But to make the vm to run on ram,it requires more than 5GB /dev/shm which can not be created with current setup.. – Blue Gene Aug 19 '12 at 15:37
You can regard the VM as an application. – Christopher Perrin Aug 19 '12 at 15:39
sorry for wasting your time.sorry... my ignorance – Blue Gene Aug 19 '12 at 15:52
You are not wasting my time. I'm just glad to help :) – Christopher Perrin Aug 19 '12 at 18:17

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