Bake-off: 4 Virtualization Suites (In One Review!)

XenSource XenEnterprise 4.0
XenSource earned kudos for its ease of use and is doing an admirable job of adding features to catch up to VMware. Still, XenSource's offering lacks the software life-cycle management features that VMware has built, landing it in second place.

At the heart of XenSource is the Open Source Xen Hypervisor, which runs on bare metal under any OS and uses a stripped-down enterprise Linux OS to supply management and I/O services for VMs running alongside it. Traditionally, XenSource has primarily offered a Linux-on-Linux solution, but the company is starting to break from tradition with its new XenEnterprise 4.0.

The 4.0 release arrives with a new XenCenter console that requires Windows XP, Windows 2003 server or Vista to run. The new console is capable of managing physical and virtual environments. XenEnterprise and the new midtier server arrive with a true 64-bit hypervisor, which now supports a lot more memory.

On the 4.0 platforms, physical servers can have up to 128 Gbytes of memory, while virtual memory can be set up to 32 Gbytes. The platform now has key features, such as support for resource pools of up to 16 physical servers with shared storage.

The resource pools provide shared configurations, allowing administrators to cover multiple servers at once rather than updating each individually. The new server also supports dynamic resource allocation for disks, CPUs and networks. Windows guests can only receive new storage dynamically. Linux VMs can get virtual CPUs and network connections dynamically.

Like the other products covered here, XenCenter 4.0 supports live migrations. XenSource matched VMware for performance of live migrations; engineers did not notice any significant delays.

XenCenter is also capable of controlling VMs on the fly. Administrators can suspend VMs to disk without changing their original state. This a huge step forward for XenSource because now developers can suspend VMs when developing applications and perform testing with different resources.

XenCenter has a ways to go until it can provide the cohesive access that large development and testing groups require when building enterprise applications. However, XenServer is the best product to use in small to midsize Windows IT shops. Despite its limitations, engineers found XenServer to be the easiest product to navigate and configure with Windows servers. This virtualization server is useful for developing and testing simple multitier applications.

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