Joins other vendors in going battery-free
The use of batteries in RAID controllers to protect the volatile cache during power outages is being phased out as manufacturers switch to the use of ‘super capacitors’ coupled with FLASH memory.
ATTO just announced this option in its ExpressSAS 6Gbps SAS/SATA RAID controllers, calling it CacheAssure. The capacitor stores electric charge while power is available, and then uses that charge to keep the circuit alive long enough for the volatile DRAM memory used for high-speed cache to be copied to the non-volatile FLASH memory.
This has several advantages. First, batteries can only preserve the memory for a few days. While this is usually long enough to handle a typical short-term power failure, it will not handle a situation, like a hurricane aftermath, that can knock out power for a week or more. The second major advantage has to do with the recurring expense of the batteries, as well as the down-time associated with replacement. Batteries are made out of nasty materials, and need to be recycled.
Finally, the staff time needed to monitor and replace the batteries is significant. While the addition of the capacitor and FLASH to the circuit adds some cost to the circuit, the lack of maintenance and battery expense quickly offsets this cost. ATTO RAID controllers with CacheAssure are available immediately.
ATTO’s announcement reminds of another vendor that uses super caps with their RAID controllers. Last year, Adaptec introduced the Series 5Z RAID Controller with Zero-Maintenance Cache Protection. And, a number of other vendors use super caps too. Among them is Dot Hill with its 2532 Premium SAS Storage Array for Direct Attached Storage.
