A while back, I posted about some of the availability/reliability problems that can arise when many workloads are hosted on the same physical server (see When organizations put a lot of eggs in one basket for more information.) Several readers pointed out that there is more to that story. What happens when desktop workloads are encapsulated and run somewhere in the network? As one might expect, similar problems of availability and reliability can arise.
Let's look at different possibilities:
- Workloads could be encapsulated using application virtualization technology and delivered to a remote system (could be a netbook, a laptop, a tablet or a desktop system). If the physical machine fails, suppliers such as AppZero, Citrix, MokaFive, Microsoft Spoon and VMware would suggest just sending the application back to the system once it is back on the air. Some also offer the technology necessary to replace user's data as well.
- Multiple virtual desktops hosted on a single PC or desktop system — products from companies such as Citrix, Neocleus, Virtual Computer and VMware allow individual workloads to be encapsultaed into virtual machines and then many of them to be hosted on the same physical laptop or desktop computer. If that physical system fails, all of the workloads and the data they were processing can come tumbling down. Several of the suppliers point out that it is simple to just reload the workload from a remote or local server. They don't have an easy answer to the question "what happens to the data being processed at the moment of failure?"
- Multiple virtual desktops hosted on a single blade PC — products from companies such as Citrix, HP, NComputing, Microsoft, Pano Logic, Wyse, and others individual workloads to be either run directly on a blade PC or encapsulated in virtual machines. If that blade PC fails, all of the workloads and the data it was processing can wind up on the floor. come tumbling down. As in the case in which the physical system was a single PC or desktop system, reloading the workload can be relatively simple. It is not always as easy to return to the exact state prior to the failure.
- Multiple virtual desktops hosted back in the datacenter or in the cloud somewhere — the same problems mentioned before can occur. Several of the same suppliers Citrix, Microsoft and VMware as well as a few newcomers, such as Skytap, suggest that it is easy to deal with such failures ... if the organization is using their software suite.
In the end, availability and reliability need to be a central part of the planning for putting all of the organization's desktop workloads in a small number of computing baskets.