Know how persistent VDI, project size affect storageDate: May 28, 2014
When evaluating storage vendors for a virtual desktop infrastructure (VDI) environment, it's important to first confirm how VDI will be architected to avoid any storage speed bumps. Factors such as persistent VDI versus non-persistent VDI and the number of desktops to be implemented should be considered to ensure storage will provide adequate performance and scalability.
During his presentation at TechTarget's Storage Decisions seminar, VDI expert Brian Madden explained storage needs for persistent VDI versus non-persistent VDI can get convoluted when speaking with vendors. Non-persistent VDI requires sharing one disk image -- meaning every time a user logs out, their settings and data revert back to the original state. According to Madden, when storage professionals perceive VDI as being an inexpensive option, this is the implementation they think of. The problem is that sharing one disk image isn't particularly useful for the majority of businesses.
"Non-persistent VDI, where we're sharing images, was a scam VDI people were putting on us five years ago," Madden said. "That usually failed because if our business environment allowed us to use non-persistent VDI, we would have been doing it with our laptops for 20 years."
Persistent VDI, on the other hand, requires separate disk images so that a user's settings and data will be saved during each log off -- which requires more storage. "I want to say [to the storage vendor] 'I have 1,000 users [and] 1,000 separate disk images, and I'm going physical to virtual in your environment. Can you handle that?' And if they can't, you buy somebody else," Madden said.
Knowing the number of desktops that will be created is another crucial factor when choosing storage. Madden explained that testing VDI is tricky -- the storage requirements for 100 users is vastly different than the storage requirements for 250 users, for example. "It's tough for us as we're architecting VDI to say, 'We're going to try this VDI thing for 100 users, [and] if it goes well, we'll go to 1,000.' Do you buy storage for the 100 users, which you know you're going to throw away, or do you buy storage for the 1,000, which is 10 times too big?" Madden asked.
"There's no magic solution here; you just have to be aware what specific steps there are for the vendor you're looking at," he noted.