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TBL Networks Announces Addition of Director of Business Transformation

RICHMOND, Virginia – March 18, 2015 – TBL Networks, a Cisco Gold Certified Partner headquartered in Central Virginia, announced the addition of Phil Stull to their team as the company’s Director of Business Transformation. With nearly two decades of focused data center experience, Stull will aid in the growth of TBL Networks and the adoption of their Limelight service offerings.

“Many businesses come to us looking for ways to strategically leverage technology. Phil’s experience and knowledge cover both sides of that equation. He’s business-minded, but also has twenty years of technology experience under his belt,” said Alan Sears, President and CEO of TBL Networks.

As the Director of Business Transformation, Stull is TBL’s technology evangelist. He serves as an advisor for local professionals who are interested in learning how TBL’s Limelight PCaaS (Private Cloud as a Service) can be directly tied to their business drivers.

“Business and technology are no longer two separate entities. They need to be purposefully and thoughtfully linked together in order to achieve high level goals. Phil offers our clients immense insight in both of these areas,” added Sears. “He understands how they work and, more importantly, how they can work together.”

Before coming to TBL Networks, Stull worked at Capital One’s IT headquarters, where he was praised as a technology leader for his work trimming IT expenses and driving innovation. Stull has a proven ability to implement technologies that result in competitive business advantages.

Phil Stull, Director of Business Transformation
Phil Stull, Director of Business Transformation

About TBL Networks, Inc.
TBL Networks is about moving forward with innovative technology. TBL empower clients’ collaboration strategy, virtualization and datacenters to do more with less. TBL delivers these advanced solutions directly where it counts the most – the desktop. Building secure and reliable solutions that introduce efficiencies in human interaction is how we see the future. For more information about TBL Networks visit:

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TBL Contact:

Alan Sears, President + CEO,, 804-822-3641

Stretched Clusters: Use Cases and Challenges Part I – HA

I have been hearing a lot of interest from my clients lately about stretched vSphere clusters. I can certainly see the appeal from a simplicity standpoint. At least on the surface. Let’s take a look at the perceived benefits, risks, and the reality of stretched vSphere clusters today.

First, let’s define what I mean by a stretched vSphere cluster. I am talking about a vSphere  (HA / DRS) cluster where some hosts exist in one physical datacenter and some hosts exist in another physical datacenter. These datacenters can be geographically separated or even on the same campus. Some of the challenges will be the same regardless of the geographic location.

To keep things simple, let’s look at a scenario where the cluster is stretched across two different datacenters on the same campus. This is a scenario that I see attempted quite often.




This cluster is stretched across two datacenters. For this example let’s assume that each datacenter has an IP-based storage array that is accessible to all the hosts in the cluster and the link between the two datacenters is Layer 2. This means that all of the hosts in the cluster are Layer 2 adjacent. At first glance, this configuration may be desirable because of its perceived elegance and simplicity. Let’s take a look at the perceived functionality.

  • If either datacenter has a failure, the VM’s should be restarted on the other datacenter’s hosts via High Availability (HA).
  • No need for manual intervention or something like Site Recovery Manager

Unfortunately, perceived functionality and actual functionality differ in this scenario. Let’s take a look at an HA failover scenario from a storage perspective first.

  • If virtual machines failed over from hosts in one datacenter to hosts in another datacenter, the storage will still be accessed from the originating datacenter.
  • This will cause storage that is not local to the datacenter to be accessed by hosts that are local to the datacenter as shown in the diagram below.


This situation is not ideal in most cases. Especially if the datacenter is completely isolated. Then the storage cannot be accessed anyway. Let’s take a look at what happens when one datacenter loses communication with the other datacenter, but not with the datacenter’s local hosts. This is depicted in the diagram below.


  • Prior to vSphere 5.0, if the link between the datacenters went down or some other communication disruption happened at this location in the network, each set of hosts would think that the others were down. This is a problem because each datacenter would attempt to bring the other datacenter’s virtual machines up. This is known as a split-brain scenario.
  • As of vSphere 5.0, each datacenter would create its own Network Partition from an HA perspective and proceed to operate as two independent clusters (although with some limitations) until connectivity was restored between the datacenters.
  • However, this scenario is still not ideal due to the storage access.

So what can be done? Well, beyond VM to Host affinity rules, if the sites are truly to be active / standby (with the standby site perhaps running lower priority VM’s), the cluster should be split into two different clusters. Perhaps even different vCenter instances (one for each site) if Site Recovery Manager (SRM) will be used to automate the failover process. If there is a use case for a single cluster, then external technology needs to be used. Specifically, the storage access problem can be addressed by using a technology like VPlex from EMC. In short, VPlex allows one to have a distributed (across two datacenters) virtual volume that can be used for a datastore in the vSphere cluster. This is depicted in the diagram below.



A detailed explanation of VPlex is beyond the scope of this post. At a high level, the distributed volume can be accessed by all the hosts in the stretched cluster. VPlex is capable of keeping track of which virtual machines should be running on the local storage that backs the distributed virtual volume. In the case of a complete site failure, VPlex can determine that the virtual machines should be restarted on the underlying storage that is local to the other datacenter’s hosts.

Technology is bringing us closer to location aware clusters. However, we are not quite there yet for a number of use cases as external equipment and functionality tradeoffs need to be considered. If you have the technology and can live with the functionality tradeoffs, then stretched clusters may work for your infrastructure. The simple design choice for many continues to be separate clusters.

Revving Up the Data Center

Every fall, Richmond International Raceway hosts a demonstration showcasing the power of advanced engineering and cutting edge technology.  When NASCAR’s “One Last Race to Make The Chase” comes to town, race fans get a chance to see (and hear) the power of converged technology in person.  On the eve of the Wonderful Pistachios 400, TBL Networks used this back drop to announce our latest advancement in the use of converged technology in the data center – the Vblock.

TBL Networks’ President Alan Sears announced that TBL Networks has achieved Vblock Qualified Partner Status, becoming just the 58th company in the world to receive this certification from VCE. With this announcement, TBL Networks can now provide it’s clients with the VCE Vblock, the world’s first completely integrated converged infrastructure offering for rapid virtualization deployment. 


Using the combined resources of four technology stalwarts – VMware, Cisco, EMC and Intel, the Vblock brings together the best of the best to create a simple yet powerful data center.  The Vblock’s converged infrastructure places virtualization, server, storage, networking, security and management in a single, prebuilt solution.  Whereas most data centers are constructed from individual components, the Vblock arrives fully integrated and test, providing users unmatched operational simplicity.

In addition, the Vblock brings together simple yet powerful customer service and support.  VCE’s partnership allows client’s access to cross-company, cross product-trained support experts.  If you need support, you will not have to ponder which vendor to contact;  VCE allows you to receive a single customer service experience.


Following the Vblock presentation, participants got a chance to view live NASCAR Nationwide action, exploring the pit area and watching as Kyle Busch won the Virginia 529 College Savings 250.

Revving up the data center might not be as loud as revving up a NASCAR engine, but with Vblock, it can be just as powerful.