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Virtual desktops promise savings and consolidation similar to what server virtualization delivers, but once again, storage is a big issue.
By Eric Siebert
Implementing a virtual desktop infrastructure (VDI) involves many critical considerations, but storage may be the most vital. User experience can often determine the success of a VDI implementation, and storage is perhaps the one area that has the most impact on the user experience. If you don't design, implement and manage your VDI storage properly, you're asking for trouble.
VDI's impact on storage
The biggest challenge for storage in VDI environments is accommodating the periods of peak usage when storage I/O is at its highest. The most common event that can cause an I/O spike is the "boot storm" that occurs when a large group of users boots up and loads applications simultaneously. Initial startup of a desktop is a very resource-intensive activity with the operating system and applications doing a lot of reading from disk. Multiplied by hundreds of desktops, the amount of storage I/O generated can easily bring a storage array to its knees.
After users boot up, log in and load applications, storage I/O typically settles down; however, events like patching desktops, antivirus updates/scans and the end-of-day user log off can also cause high I/O. Having a data storage infrastructure that can handle these peak periods is therefore critical.
Cost is another concern. The ROI with VDI isn't the same as server virtualization, so getting adequate funding can be a challenge. A proper storage infrastructure for VDI can be very costly, and to get the required I/O operations per second (IOPS) you may have to purchase more data storage capacity than you'll need.
Expect to spend more time on administration, too. Hundreds or thousands of virtual disks for the virtual desktops will have to be created and maintained, which can be a difficult and time-consuming task.
This was first published in March 2011