Are there virtual desktops that traditional hard disk storage can support, and beyond that you should be on solid-state drive storage? Or is it not that simple?
It's not that simple. The number of virtual desktops supported depends on IOPS required by all of the virtual desktops in a worst-case or peak scenario. Then you'll want to match that up to the peak IOPS of the VDI server or servers, storage and storage network. Not enough supporting IOPS means slower response times and user dissatisfaction.
The biggest VDI performance issue to account for when evaluating HDD vs. flash storage is what's known as a boot storm. The boot storm occurs at that time of day when everyone turns on or boots up their virtual desktop when they come into work. This is usually first thing in the morning, although it can occur at other times during the day. Users expect a boot-up to take the same amount of time, regardless of whether they are on a standard desktop or laptop. Booting is heavily I/O-intensive. Failure to boot up in that time frame leads to significant user dissatisfaction as well as undesirable user behaviors such as leaving the machine on all the time.
This was first published in December 2012