Virtualization is hot. Everyone wants to get in on the action, make better use of their existing hardware investments, gain flexibility, and create simpler, more cost-effective data centers.
But not all aspects of virtualization are rosy. In fact, looming ramifications of server virtualization are slowly making themselves known, particularly in the area of storage performance.
A recent article from Computer Weekly spells out several things to look for, but this paragraph is especially relevant
Evaluate performance and latency. Virtualization platforms can sometimes experience latency when accessing directories -- especially directories with many small files. Some virtualization products attempt to compensate for this latency by using file acceleration techniques. Others may handle performance issues using tactics like volume rebalancing and migrating lightly used files to other storage resources on a lower tier or another virtual volume with lower utilization. Ultimately, it's important to test any virtualization system and see how it performs under actual load conditions.
The premise is simple. One server image on a single server accessing data is relatively straightforward. Multiple virtual machines across multiple servers accessing the same storage system is susceptible to performance and latency impacts and customers need to be aware of this.
Server virtualization alone cannot revamp the data center. But complimenting server virtualization with solutions that also address the storage side of the equation will lead to tremendous efficiencies. Centralized storage caching delivers the storage performance needed to power large server virtualization deployments.