August 31, 2010
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Sitting here in the VMworld keynote, I’m finally allowed to discuss a pet project our team has been working on for VMware around stateless desktops with View 4.5. The Reference Architecture brief is released now, and the “full” reference architecture with full detail around the architecture will be out in the next month or so.
Stateless desktops are all about the use of local host-based solid-state drives, coupled with a consistent operating system image, to allow enhanced performance, linear scalability, and a reduction in cost. It is important to realize that the OS, Application, and User data must be compartmentalized in order to use this design. However, in our opinion this is the key to being able to use VDI in a truly flexible way. It is how we design VDI. Personally, I think the model will open many eyes to why NOT to use persistent images. It simply isn’t efficient. The costs show it!
What is really interesting about this design is many of the issues that require intense storage design to address simply vanish. Boot storms, antivirus scans, login storms, worrying about the IOPS; all are at the least mitigated and at best are no more. A foundation of simplicity perhaps? For a highly scalable and manageable architecture, a level of simplicity is a requirement. You can build two hosts or thousands, and this design can scale without much of a difference in the cost per user for core compute, software, storage, etc.
Last – and perhaps a bit of a teaser for the upcoming full RA – this type of design becomes a local SSD capacity discussion today. It is the Achilles heal of the design, however easily mitigated today with multiple SSD’s. With ever larger and faster SSD’s coming out in the market very soon, I don’t think this is a real limiting factor. The scaling per-host is now potentially NOT about memory or CPU, which is a drastic change in what everyone typically discusses. We are seeing the VM-per-core limited primarily based on how many we can smash on the drives, and especially with a host with 12 cores it gets quite interesting.