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What's different about storage for virtual desktops?

Virtual desktop infrastructure projects will create renewed demand for high-performance storage. Not surprisingly, performance and management simplicity will be prized.

John Webster Special to CNET News
John, a senior partner at Evaluator Group, has 30 years of experience in enterprise IT storage, spanning mainframe and open systems environments. He has served as principal IT adviser at Illuminata and has held analyst positions at IDC and Yankee Group Research. He also co-authored the book "Inescapable Data Harnessing the Power of Convergence."
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John Webster
2 min read

It is often said that data center-level server virtualization projects created a renewed demand for networked storage, both NAS and SAN.

If that's true, then efforts to virtualize desktops--aka virtual desktop infrastructure (VDI) projects--will create renewed demand for high-performance storage, both network-attached storage (NAS) and storage area network (SAN).

Storage performance is a major determinant in successful deployments of VDI. Why? VDI is a storage input/output-intensive environment.

When you lift the hood to find out what's going on inside a disk array that's supporting virtual desktops, you see the following:

The typical virtual desktop running Windows apps is moving almost 1MB of data per second with an access rate of approximately 10 I/O's per second (averaging 100KB per I/O).

Characterizing a rule of thumb for the I/O profile for VDI can be very difficult. VDI generates data blocks that vary dramatically in size, from 512 bytes to 2MB. Read/write ratios can vary from 30/70 to 60/40. Also, accesses are almost completely random.

All of the which creates a storage environment where both performance and management simplicity are appreciated. Some of the attributes of modern storage architecture will be in demand as a result. These include:

  • Solid state disk (SSD) for performance, implemented within the storage array level as either "tier zero" in a tiered storage array or as cache.
  • The ability to generate thousands of writable snapshot copies to quickly provision desktop images.
  • Thin provisioning to allocate disk capacity on demand rather than pre-allocating capacity.
  • Automated provisioning assistance.

VDI is quickly rising in popularity within the education, health care, and government segments. Others will join during 2012. Getting the storage environment right will be a critical consideration for all however as IT administrators across the business and organizational spectrum will witness the same basic storage requirements. Therefore, having some way to run a reliable test phase before a major production VDI deployment is an absolute requirement. Modern storage architectures that support the attributes outlined above will also be highly sought-after.