[CentOS] OT: Recommendations for a virtual storage server

Hi all,

I need to install a virtual machine acting as a virtual storage server under CentOS 5.x (using kvm, xen, virtualbox or vmware). This virtual storage machine needs to server storage to another ESXi server and at the same time to the host where is installed.

This is due to the limitations of hardware I have available. Both hosts needs to server several machines.

It is very important that the virtual machine consumes the least resources possible (host has 5GB RAM and i need to run three virtual machines minimum, including this storage server as a virtual machine).

What can be better solution: CentOS, NexentaStor, openfiler ...??

Many thaks.