When it comes to PCIe NAND flash cards, like those sold by Fusion-io, Texas Memory Systems, Micron or Virident Systems, which can be used in all-flash arrays or in application servers themselves, prices can go through the roof, but so does performance due to the higher-speed interconnect and the proximity of the flash storage to the server processors.
Even so, not everyone "gets" why flash-based PCIe cards are so expensive. Chris Rima, supervisor of infrastructure systems for the Information Services Department at Tuscon Electric Power, a subsidiary of UniSource Energy Corp., paid only half of the retail price for flash cards to accelerate the performance in his company's NetApp into 3170 NAS arrays. That means he paid $30,000 for each card.
Tony Edlebrock, senior systems administrator with Tuscon Electric, said NetApp's flash cards, called Performance Acceleration Modules (PAM), boosted the performance his PeopleSoft and Oracle customer care and billing reporting system to the point that it cut the nightly batch process in half, from from between 8 and 12 hours to 4 to 6 hours.
"The nice thing about flash cache is you just put them in and they begin to improve performance everywhere. Protocol latency went down and throughput shot up," Rima said. "I just don't get why they're so expensive."
According to NetApp, using its PAM flash cards in its NAS arrays makes it possible to reduce the number of disk drives by as much as 75 percent while achieving the same or better performance.
Flash strategies, use cases
However, because of the exorbitantly high cost of some PCIe-based flash cards, their purchase should be based on multiple business use cases, not a single task, Rima said.
Tuscon Electric Power uses its six flash cards on the front end all of its PeopleSoft and Oracle databases. The cards also act as front-end cache for two-thirds of Unisource's 500 VMware virtual machines, GIS mapping systems as well as databases that manage power outages. The cards have hold between 40TB and 60TB per NAS cluster.
When the online auction site had problems meeting the I/O storage demands of business units starved for more VM deployments, its quality-assurance division had an idea: Swap out hard disk drive-based arrays with SSD storage.
After replacing 100TB of storage in a year, eBay experienced a 50 percent reduction in standard storage rack space, a 78 percent drop in power consumption, and a five-fold boost in I/O performance. That speed boost now allows eBay to bring a new VM online in five minutes, compared with 45 minutes previously.
The online auction site's quality-assurance division had been using both NAS and a SAN prior to deploying modular SSD arrays from Nimbus Data Systems. It began by deploying a single 2U (3.5-in high) Nimbus S-class SSD system and HALO storage operating system a year ago.
Today, eBay has 12 SSD arrays with capacity that rivals the amount of traditional hard drive storage used, said Michael Craft, eBay's manager of QA Systems Administration.