How VMware’s Announcements Will Impact Blade Servers

As we near the end of VMworld, I thought I would take some time to highlight a couple of announcements that could impact the way people use blade servers with VMware vSphere.

End of the vTax – Great News for 4CPU Blade Servers

Probably the biggest announcement from VMware was the end of the vRAM entitlement.  When VMware released vSphere 5, the licensing program was modified to include a limit on the amount of virtual machine memory, or vRAM, that could be used on a vSphere 5 host based on the vSphere edition purchased (see chart below for specifics.)  On Monday, August 27, 2012, VMware announced the vRAM this limit would be no longer effective beginning Sept. 1, 2012.  Why is this big news to customers?  Let me explain.

vSphere 5 vRAM Entitlement

[Previous vRAM entitlements per edition]

Since the vRAM entitlement was per CPU, customers with larger servers were impacted the greatest.  For example, a customer running VMware vSphere 5 Enterprise Plus edition with a blade server with 4 CPUs was capped at 384GB of vRAM (64GB x 4 CPUs).  Now at first, that seems reasonable, but once you look deeper, it was a huge limitation.  The Intel Xeon E5-4600 based servers have 4 memory channels and 48 DIMM slots, therefore in order to reach 384GB of RAM, while keeping the memory balanced, you need to:

a) use 48 x 8GB DIMMs – uses 3 DIMMs per channel (DPC) and leaves no room for expansion

b) user 16 x 16GB DIMMs plus 16 x 8GB DIMMs – which uses 2 DPC and leaves room for expansion, but costs more.

If this customer wanted to bump up to 512GB, they would have to buy two more vSphere 5 Enterprise Plus licenses which would have entitled them to have 576GB of vRAM (6 CPU licenses x 96GB) adding an additional $6,990 ($3,495 per license U.S. List) of licensing cost per host, excluding Support and Subscription (SnS.) 

With the removal of the vRAM entitlement from VMware vSphere licensing, customers now have the flexibility to run as many virtual machines as they need taking advantage of all the physical memory.  Less licenses and the freedom to choose any memory configuration (see below) that they may need. 

Balanced Memory Configurations for Blade Servers with Intel E5-4800 CPUs

[Balanced Memory Configurations for Blade Servers with Intel E5-4800 CPUs]

Enhanced vMotion – a penalty for blade servers?

The last announcement that I’ll mention is around the release of VMware vSphere 5.1.  One of the most talked about new features within Sphere 5.1 is “Enhanced vMotion” which in summary gives users the ability to migrate virtual machines from host to host without a storage network.  This is a great feature for small environments who want to have vMotion mobility without sharing storage, as it allows for the use of internal server storage instead of external shared storage.  Architecturally, rack or tower servers is a more suitable server platform for customers who value using vMotion with local storage since they utilize anywhere from 16 – 32 internal drives whereas a blade server has 2 – 4 drive bays.  Of course, users could take advantage of storage blades (which sit in the blade chassis along with the blade servers) but they are typically iSCSI based, not direct attached, and would therefore be considered a storage network.  In reality, environments that would benefit from using Enhanced vMotion are probably not ideal for blade servers anyway, but only time will tell if it impacts blade server sales.


For more information about all of the features of VMware vSphere 5.1, check out Jason Boche’s blog at


Kevin Houston is the founder and Editor-in-Chief of  He has over 15 years of experience in the x86 server marketplace.  Since 1997 Kevin has worked at several resellers in the Atlanta area, and has a vast array of competitive x86 server knowledge and certifications as well as an in-depth understanding of VMware and Citrix virtualization.  Kevin works for Dell as a Server Sales Engineer covering the Global 500 Midwest and East markets.