If there is a consistent sales pitch for any variety of solid-state technology out there, it usually highlights its speed, compared to traditional hard disks. But it is important to recognize that flash performance does level off as drives are used.
Administrators trying to accurately determine what kind of performance boost flash will provide can do so by measuring performance from a device's so-called steady state, said Dennis Martin of Demartek LLC, in a recent Storage Decisions presentation.
"You don't want to test it fresh out of the box. If you buy a brand new SSD, whether it's a PCIe card or a drive or anything else … when you get it fresh from the factory, there haven't been any writes, so it's fresh," said Martin. "Every page is ready to be written on … so it operates very quickly. But as you write to it and you start to delete data and update things, just because of the nature of flash, the performance starts to slow down."
Martin said Demartek runs I/Os through a device when it is new in order to get it to its steady state before administrators begin application testing.
He said admins interested in learning more about the Storage Networking Industry Association's "Solid State Storage (SSS) Performance Test Specification" can learn more by visiting http://www.snia.org/tech_activities/standards/curr_standards/pts.
The organization offers testing protocols for enterprise and consumer-grade levels, said Martin.