Citrix Hypervisor Review

High-availability options in a cluster are good.

We were able to create a very inexpensive (nearly free) cluster of VM hosts.

Permissions granularity was very limited - we could not assign permissions on anything smaller than the entire cluster. Support for OS'es without paravirtualization-friendly device drivers was very limited - couldn't run some versions of Linux.

6 months

Clustered-host hardware needed to be identical, all-or-nothing permissions didn't work well for VM's owned by different teams.

Lots of errors, which may or may not have been important.  It was tough to assess the health of the cluster.

n/a - we used the free, open-source distribution of XenServer.

Used VMWare, before and after. VMWare was more expensive.

Initial software setup of XenServer is very simple, but the hardware setup is more complex. Switching and shared-storage infrastructure needed to be mapped out in advance (which is true for any VM-host-cluster environment).

in-house

Also tried oVirt, the FOSS project, similar to Red Hat Enterprise Virtualization. This had some very promising features, but was difficult to implement, and had some hardware and OS compatibility issues when running on CentOS.

Citrix or third-party software would probably make it more flexible and powerful than the plain, FOSS XenServer components.