Archive for June, 2010

Single Points of Failure

Single Points of Failure. We all know and fear them. It’s the one thing that can bring our infrastructure to its knees, and it’s what we as engineers, architects, and consultants strive to avoid in our environment. Any seasoned technical professional can quickly identify and remediate a single point of failure in the infrastructure, but I’ve noticed a lot of people overlook one huge single point of failure in their environment.

Recently, it was announced that the company I work for was being bought out and that we would enter a merger. Obviously, some people felt the risk was too great and have decided to move on to new opportunities. During this exodus, I’ve noticed a lot of people spending their last two weeks documenting and offloading their knowledge of some aspect of the environment because they were the only ones up to that point who knew it. Being the sole holder of a piece of knowledge about your environment creates the biggest single point of failure of all, yourself. Read more…


Desktop Virtualization?

Yesterday, I had a Sr. VP approach me and ask me about my technical experience with desktop virtualization and my opinion on the options. Having managed a small VDI pilot at CSC of about 100 desktops using Citrix’s XenDesktop and tinkering with VMware View in the original pilot comparison, I felt I had enough experience to speak on the two different products.

The goal is to get some sort of small pilot together, with a scope of 10-15 virtual desktops to be tested via existing PCs and possibly a thin client or two. The main concern is with us having a lot of branch offices that have processes that must be run daily. In the event they lose a connection to the data center, we need to find a way to ensure these processes get complete daily, even if the transmission takes place at a later time.

As of now, there is no preference with a vendor. We use Citrix XenApp now and also are heavily using VMware vSphere, so both vendors are liked and we have experience with both. With this thing having the potential to take off on a full-scale level eventually, I’d be curious to hear your experiences and stories with both products. Please try to avoid turning this into a pissing match of Citrix vs. VMware. I just want general opinions on your deployments.

CPU Ready: Over Built VM or Over Utilized Host?

When talk performance with any virtualized server environment, CPU Ready is a common key indicator of how well your VM is performing. However, its not always a cut and dry explination as to why your CPU Ready times are high.

To start, for those that aren’t aware, CPU Ready is:

The amount of time a virtual machine waits in the queue in a ready-to-run state before it can be scheduled on a CPU.

This means that a VM is ready to process something, however, it has to wait because the CPU resources it requires are not available on the physical host.

Before we examine causes of high CPU Ready, lets try to look at what are acceptable values for CPU Ready time. Unfortunately, there is no hard set value to say ‘Yep, your CPU Ready has crossed the ‘its bad’ threshold.’ General rule of thumb is that your CPU Ready time not be higher than 200ms if being checked in the vCenter performance charts, or 5% if being checked using the esxtop command. Again, this isn’t a hard set value. Your VMs role may require less CPU Ready time for more critical functions, or may be more lenient to longer CPU Ready times as well. It all depends on your environment, and its up to you as an admin to determine what works in your individual environment.

Read more…

Citrix + iPad

June 17, 2010 1 comment

Unless you are living under a rock, you know that the iPad has been a huge success in the consumer market and its starting to trickle into the business world. No doubt, many I.T. Professionals have had someone in upper management come to them and say ‘I’ve got this new iPad, can I use it for business use somehow?’

Well, the answer is yes, thanks to Citrix’s iPad application Citrix Receiver. Receiver is an application that connects with your Citrix environment to access your applications right from your iPad. It even works in conjunction with XenDesktop allowing you to publish full desktops to your iPad user base.

While there are some limitations with this application, namely the requirement of a Access Gateway in the DMZ, VPN Access, or some other sort of network configuration allowing your users into your network remotely, and issues with applications looking for the C: drive of a client machine, all and all I think its a great app. It’s something I use personally when I’m on call instead of lugging around a laptop. Besides, lets be honest; I look far cooler using my iPad than just some generic laptop.

Citrix Receiver is available for the iPad via the AppStore. It is also available for the iPhone, iPod touch, and other smartphone devices, but hey, who wants to access applications on such a small screen.

Season of Changes

As you can see, I have been absent for a while now. The reason for this absence is due to my career taking a turn for the better and me accepting a position away from CSC. I recently accepted a senior position with a company called The South Financial Group. They are a bank holding company based in the Southeast. My new position will entail me working more closely with a different aspect of virtualization; application virtualization, mainly with Citrix. During my time at CSC, I worked closely with Citrix products, and hope to utilize those skills in conjunction with my experience with other virtualization technologies to better both myself, and my new employers.

I will still be involved with VMware, though not on a day to day role, so topics about server virtualization with ESX will still be a focal point of my post. You will also start to notice some Citrix topics creep in as well.

My new position will allow me more time to focus on sharing my thoughts and ideas here as well, so look for me to be a lot more active now. You will also notice a new design theme for the site. I figured since I’m changing things in my career; why not change things here as well. Hopefully both changes will be for the better.

I look forward to continue to share information with my fellow virtualization colleagues.

Categories: General