Virtualization

In my last post I explained a memory reclamation technique called Transparent Page Sharing. This post is dedicated to the Balloon driver method. The first thing to be clear about is that Memory Ballooning is a technique that is only engaged when the host is running low on physical memory. If you have a host with 60 GB of physical memory available and the virtual machines are only allocated a total of 30GB of memory, then you may never need to know what memory ballooning is all about. However if you are over committing your hosts then this is an important topic to review. ...

HP Enterprise class storage has just entered the mid range market. Today HP announced the HP 3PAR StoreServ 7000 class which includes two devices; the HP 3PAR 7200 and the HP 3PAR 7400. The 7200 starts at $25k for the 2U device and the 7400 (seen below) is less than $40K for a 4U device. I’m very excited about this announcement because now HP has a storage device with the features that everybody wants and it’s now affordable for a smaller sized organization. HP has seemingly targeted one of it’s own devices with this announcement (the HP EVA) since it has been very popular with the mid-range business. They’ve even included some tools to migrate data from the EVA to the new 3PAR. I seriously doubt that the EVA will entirely go away, but the new big brother is going to steal some of their thunder. ...

While I was studying for the VCAP-DCA I realized that many people might not have access to a lab that includes the capability to do VMDirectPath I/O. My own lab is using nested ESXi hosts inside of VMware Workstation so I don’t have access to DirectPath either, but I was able to borrow some equipment in order to test my skills. If you don’t have access to this type of equipment but want to study for the VCAP5-DCA, the below setup should suffice for you to learn it, as the setup is not very difficult. ...

I really wanted to test out some VMware Site Recovery Manager scenarios and realized that buying SANs, servers and networking equipment was quite expensive. I also didn’t have a lot of space in my house that was available for running all of this equipment. After completing my VCP5 I was given a copy of VMware Workstation 8 and thought that I might be able to build a nested virtual environment, where the ESXi hosts themselves were virtualized inside of workstation. (Don’t worry, virtualizing a virtual host doesn’t warp time or space, it’s safe.) ...

A question often comes up about what to do when you have a segmented virtual network that needs to be able to traverse subnets. This might happen if you’re doing some testing and don’t want the machines to contact the production network, or perhaps doing a test SRM failover and having the virtual machines in their own test network. Virtual machines in subnet (A) might need to contact other virtual machines in subnet (B) but don’t have access to the physical router any longer, so they can’t communicate. To solve this issue, how about we try a virtual router? ...

Emulation and Virtualization are not the same thing. In many cases you’ll hear them used interchangeably but they are different concepts. Emulation Emulation consists of taking the properties of one system and trying to reproduce it with a different type of system. When it comes to computers, you may have seen some software emulators that you can install and run on a PC or MAC, that will reproduce the characteristics of an older system such as a Nintendo or other gaming console. As an example you could then perhaps run Super Mario Bros. on your work desktop (I am not advocating the playing of video games at work). In this case the software emulator is mimicking the gaming console so that the game could be run inside the emulator, even though the underlying hardware is an x86 architecture. ...