K12IT

In the previous two installments (Part I and Part II), I described the steps involved in setting up and the differences between a Hyper-V and VMware vSphere environment. This final segment will go over the pros and cons of each environment.

VMware is the 800 pound gorilla when it comes to virtualization technology. Thus, it has tens of thousands of installed environments, users, consultants, etc. The product is in it fourth major release and is the gold standard to which all virtualization technology is compared. BUT…there's always one them, it's expensive. Yes, you'll save money in TCO, yes it's the "industry standard", yes it's more capable than Hyper-V. But, in these budget slashing times, $10,000 in licensing for a small environment is significant. Does that mean I think Hyper-V is better…no. I'm just stating an obvious fact that any business manager is going to make known.

VMware vSphere 4 Pros:

As stated earlier, VMware is the "industry standard" when it comes to virtualization. Support is included with the purchase of VMware and is part of a maintenance agreement. I can attest to VMware's tech support for the couple times I've had to call them. Calling any company's tech support rates just above getting a root canal for me, so it's refreshing when you get to talk to somebody that knows something about their product.

VMware is spectacular with memory management and will allow you to overcommit memory to the VMs. What does that mean? Let's say you have a physical ESX server with 64GB of memory and 20 VMs configured with 4GB of memory. Simple math says you would need 80GB of memory in the server. Not the case, in fact I would wager in that scenario for a normal school district, the server would only be using about 40GB of memory.

VMware has a staggering amount of add-on components for Vsphere, specifically vCenter. Many are probably beyond what a normal school district would use (or could afford), but it's nice to know they exist. One of the most interesting ones is Site Recovery Manager (SRM). SRM enables a entire virtual data center to be brought online in another location for disaster recovery…automatically. It also allows you to test out a DR plan without disrupting the production environment.

Depending on the size of your school, there may be separate network and systems administrators. One of the complaints among network admins relating to VMware is the loss of control with virtual switches. vSphere has an optional Cisco Nexus integration (in their Enterprise Plus license). Utilizing a Nexus 1000V virtual switch, almost any function that would be found in the Nexus series of switches, can be implemented in a VM. Think QOS from core to VM.

Previously, ESXi's diminutive size was discussed. Since there is no longer a service console in the hypervisor, the attack vector for the hypervisor goes way down. That doesn't mean you never have to upgrade an ESXi server, but it does reduce the amount of updates.

Finally, if you support multiple operating systems in you district or just like to play with different OSes, vSphere supports almost any operating system you can think of (Linux, Unix, Windows back to Windows 3.1, NetWare).

VMware vSphere Cons:

I've already stated that VMware can be a bit pricey, but how pricey depends on which flavor you get; which leads me to the second negative for VMware…which version do you buy? There are 4 licensing models for vSphere with the price and feature set going up for each level.

Already mentioned, was the fact that ESXi has a very strict hardware compatibility matrix, thus older hardware may not be compatible. If you are comfortable with Windows and the Microsoft way of doing things, the learning curve and interface for vSphere will take some getting used to.

Hyper-V Pros:

Hyper-V is less mature than its VMware counterpart, but there are a couple areas that make it shine in comparison, especially for educational institutions. Hyper-V will run on anything that will run Windows Server 2008, so if you want to play with it, grab that old server off the shelf and have at it.

It's Windows! Most schools are already running Windows servers, admins are familiar with Windows, thus slipping in Hyper-V is "just another Windows server." Granted, there still is some knowledge to gain and if you want redundancy, a Microsoft cluster needs to be configured, but at its core, it's just Windows.

Since Hyper-V is Windows, it's compatible with any volume shadow copy service (VSS) backup software, like Microsoft's own Data Protection Manager. Each VM can be backed up as a simple VSS snapshot and since it is VSS, services like SQL and Exchange are backed up correctly.

Finally, Hyper-V's huge advantage is it's price tag. If you buy the data center license for a server, you are covered to run Hyper-V on it. You still need to purchase VMM and System Center Operations Manager if you want to have a fully managed and monitored environment, but the educational costs for Microsoft products make it very attractive. I won't give exact figures because educational costs for Microsoft products vary state to state, but initial software costs can be up to 75% less. In a time of budget crunches, it's hard to ignore.

Hyper-V Cons:

Take this however you want, but Hyper-V is not as mature as VMware. Does that mean it's not as good? Not necessarily. For most education environments it will be good enough, but if you need some of the add-ons that VMware offers or the Nexus virtual switches, your choice is clear.

Hyper-V has a much smaller supported operating system portfolio than VMware. It's pretty much limited to Windows 2003 and up, SUSE Enterprise Linux 10 or 11 and Red Hat Enterprise Linux 5.2 and up. For most districts that only have Windows servers, this shouldn't be an issue (unless you have Windows 2000 servers still running).

The final drawback to Hyper-V is there is no included support with the purchase. This can be both good and bad. Some users will be happy, as they will never call support and aren't paying for something they won't use. Others will be very uncomfortable without the ability to call support and will need to purchase additional support options.

In conclusion, is there a clear winner? Not really. If your environment is heavily invested in Microsoft technology (particularly SCOM, SCCM, WSUS, etc) and you have experienced Windows admins, then clearly, Hyper-V will slide right into your environment at minimal cost and headaches (training, set up time). If you have a mixed environment, looking to get all the performance you can out of your virtual infrastructure or don't want to have to set up other services to monitor the infrastructure, VMware may be better suited to you.

In Part I of our Hyper-V/VMware bake-off, we looked over the environment and installation. Part II will involve network and storage allocation.

Once the hypervisor is installed on the host, almost everything is done on the management servers (VMM or vCenter). In our environment, we wanted to use multiple network connections for redundancy and use those network connections for multiple VLANs (virtual local area networks). VLANs help group like traffic and segment the network's broadcast domain. In order to do this, the switches the physical hosts connect to must support VLAN trunking. To maintain maximum redundancy, the two network connections should be split across two physical switches. Configuring the hosts to support trunking and redundancy is different for Hyper-V and VMware. Hyper-V requires that the vendor's NIC drivers be installed and configuration for link aggregation and/or failover is done within that software. In our servers, the Intel NICs did not have a command line interface for configuring VLAN trunking, so Windows Hyper-V Server (non-GUI) could not be used and the full version of Windows Server 2008 R2 was required.

For VMware, as long as the NICs are on the software compatibility matrix, a virtual switch is created and NICs are assigned as uplinks for that switch. Link aggregation and failover are automatically configured.

Both systems will allow for physical separation of the network as well. In both scenarios, separate NICs are configured and connected to separate switches. This is useful if you want to host servers that belong in a DMZ or perimeter network, but want to prevent the possibility of VLAN hopping.

VLAN assignment can be done in the guest VM operating system or in the Virtual Network Manager for Hyper-V. VMware uses Port Groups which are, in essence, VLAN assignments associated with a virtual switch. Assigning a guest VM to a Port Group associates the VM with that VLAN. Both allow for the creation of a private network that is only accessible by a VM "virtually" connected to it. This is useful for isolating database servers for web applications.

Storage for Hyper-V is handled similarly to a normal Windows server with one notable exception. Our environment was using fibre channel storage using two HBAs. Microsoft MPIO was configured for basic failover, but we could have installed (and paid for) EMC PowerPath for greater flexibility. The storage was presented to both hosts and configured in Microsoft Clustering Management application as a shared resource. In order for both hosts to access the same LUN, at the same time, the storage must be configure as a Cluster Shared Volume. This was introduced in Windows 2008 R2 and is needed for Live Migration and instant failover.

For VMware, the storage is presented to both hosts and is formatted as a VMFS volume using vCenter. The storage is then accessible to all the hosts and multiple paths are automatically configured.

Both systems can use remote storage for keeping VM templates and ISOS (SMB shares for Hyper-V and NFS shares for VMware). Creating templates drastically reduces the time to deploy a new VM and keeping ISOs of those often needed install discs saves time finding the appropriate CDs/DVDs.

Next time, the results of the bake-off. Stay tuned!