VDI

If you install the Citrix XenDesktop 7.6 Virtual Desktop Agent (VDA) on a small Windows 7 VM, you may be in for a big surprise, and not a good one. This article documents issues I have experienced and how to work around them.

This is the third article in a multi-part series about building and maintaining an inexpensive scalable platform for VDI in enterprise environments. Previously in this Series In the last article I explained that shared storage should be avoided, for two reasons: it is (very) expensive, and you, the VDI guy, are not in control. The storage guys are.

This is the second article in a multi-part series about building and maintaining an inexpensive scalable platform for VDI in enterprise environments. Previously in this Series I started this series by defining requirements. Without proper requirements, everything else is moot. Remember that we are looking at running typical enterprise desktop workloads, we are trying to centralize desktops and our primary desktop hosting technology is multi-user Windows, aka RDS/XenApp.

This is the first article in a multi-part series about building and maintaining an inexpensive scalable platform for VDI in enterprise environments. Requirements Before we can even start to think about a possible architecture, we need requirements. Only requirements enable us to make choices that benefit the customer. Without proper requirements we are not building for the real world but for some alternate reality. Please keep in mind when reading this article that the solution presented here only makes sense for you if your requirements are similar.

I had to troubleshoot a case where it suddenly was not possible any more to connect via ICA/HDX to freshly installed Windows 7 VDI machines. As it turned out, the root cause was a combination of Microsoft disabling legacy technologies and Citrix relying on them.

When you move users from a physical PC to a VDI environment you may find that they are not too happy with their new machine’s performance - it happened to me. To quantify things I took a series of measurements comparing the old PCs we migrated away from with both VDI machines and the new PCs available to some.

[Update on 29/06/2012: added tests 5 and 6 with RAID controller cache and Atlantis Ilio] When a 400 GB SSD comes nearly at the price of a small car, you expect a lot, performance-wise. At least I did when I got my hands on two drives from HP’s enterprise performance series. Read on to find out if that hefty price tag is justified.

The HotPlug functionality of VMware ESX(i) 4 and 5 has the negative side effect that it is easily possible to “eject” hardware devices from inside the virtual machine, completely removing the respective device from the VM configuration. This is especially bad if it happens to the network card, and others have already described how to prevent that from happening (e.g. here and here).

A desktop delivered from the cloud, accessible from everywhere, providing just the right amount of computing power for the task at hand, maintained by the cloud provider and paid for only when used - a dream? Or a commodity in ten years’ time? Time will tell, but in the meantime let us find out if such a virtual wonder device is even possible.