Fujitsu Ltd. is rolling out two new disk arrays today at the low end of its Eternus midrange product line, including Fujitsu's first single-controller Eternus configuration. The new arrays offer a new predictive failure mode for RAID rebuilds, and take a different approach to battery-backed cache.
The Eternus DX60 and DX80 replace the Eternus 2000 at the low end of the product line, which also includes the 4000 and 8000 models. The DX60 represents "a new and big step for Fujitsu," said Jim DeCaires, storage product marketing manager at Fujitsu America.
DeCaires said Fujitsu has resisted single-controller versions of even its low-end arrays in favor of offering high availability in the design of all of its products. But with this release, the DX60 single-controller version launches with a starting price of between $5,000 and $6,000. "We managed to convince [Fujitsu headquarters] that it's OK," DeCaires said.
RAID rebuilds lets customers set thresholds for when a DX system's drive has failed. Once a disk's behavior approaches or meets those thresholds – but before it has fully failed – Fujitsu will bring in the spare drive and initiate an automated RAID rebuild. "Not waiting for a drive to fail means less impact to performance and system operation for RAID rebuilds," DeCaires said.
These systems also take a new approach to preserving data in cache in case of a power failure. Higher-end systems that aren't kept running with generator power often use battery cells that preserve data in cache until the array can be powered back on, so that data isn't lost. Some systems also use batteries to keep the cache alive long enough to destage data from cache to spinning disk.
Fujitsu's approach with the DX series is to back up cache with a capacitor, an electrically charged circuit that charges up quickly and holds energy for a few minutes, or long enough to destage data to Flash disk. "The problem with batteries is that they have a fixed life of two to three years," DeCaires said. "A capacitor can theoretically last forever."
Jeff Boles, a senior analyst and director, validation services at Hopkinton, Mass.-based Taneja Group, isn't so sure how much of a concern battery lifecycle is to most customers. He said that while batteries have a finite life, they tend to last longer during power failures and leave more time to destage or preserve data before the array is recovered. Boles said Flash can also solve the problem of preserving data during a failure.
"It's an interesting use case for Flash disk," he said. "I expect everyone's going to be going in that direction. It makes more sense to destage to Flash quickly than waiting with battery-backed cache for the array to recover."
Fujitsu emerges from reorganization
This is Fujitsu's first storage product announcement since the parent company combined separate entities for different product types within the United States into one consolidated company called Fujitsu America. Fujitsu America was formed out of Fujitsu Computer, Fujitsu Transaction and Fujitsu Consulting. While traditionally strong in Asia and Europe, Fujitsu's brand has lagged behind competitors in North America.
Boles said Fujitsu isn't known as the most innovative storage company, but the DX series' redundancy and data protection features are unique for a midrange system. "Typical Fujitsu – slow and steady wins the race," Boles said. "They have an exceptional focus on data integrity and reliability, and make slow, incremental changes while they maintain quality."