The Amplistor XT Storage System now supports 3 TB SATA drives in its new AS30 module, allowing it to hold 30 TB in a 1U box and scale to 1.2 PB in a rack with 40 modules. The AS30 will eventually replace Amplidata’s AS20, which holds 2 TB drives and 20 TB in one appliance.

Amplidata claims the AS30 uses about 30 percent less power than the AS20, requiring 2.2 watts per terabyte when idle and 3.3 watts per terabyte when in use. That’s about the same power of a 60-watt light bulb for the entire 30 TB module.

“The really big thing is the power consumption is just over 65 watts, when powered and idle with no disk activity,” said Paul Speciale, Amplidata’s VP of products. “When there is activity, it consumes 3.3 watts per terabyte. But just because of the low performance, these systems can go tens of gigabytes per system so you are not giving up on performance.”

Amplidata’s storage platform is designed for cloud archiving of media and entertainment files, and “big data” file storage. Amplidata sees the media and entertainment industry as a key target for the larger drives.

The vendor improved its BitSpread erasure coding software and data management with its latest AmpliStor XT software released earlier this month.

Randy Kerns, senior strategist at Evaluator Group, said erasure code-based technology becomes more important with higher capacity drives because there is a greater probability of drive failures in the larger drives.

“As you get to higher capacity drives, you have a greater exposure to a second drive failure and rebuild times are longer,” Kerns said. “With that exposure, the probability goes up. Two terabyte drives typically take eight hours to rebuild in a normal system, so it becomes more important when you go to three or four terabyte drives in a multi-petabyte system because you have a higher probability of a problem happening. Media and entertainment is very sensitive to these issues and Amplilidata is targeting that market.”

Amplidata’s AS30 has a starting price of under $0.60 per Gigabyte.

The new protection technology has been called several things. The name most associated with research done in universities is called information dispersal algorithms, or IDA. Probably the more correct term as it has been implemented is forward error correction, or FEC. Another name used based on implementation details is erasure codes.

The technology can address the loss of a disk drive that RAID was targeted to protect. It can also prevent the loss of a data element when data is distributed across geographically dispersed systems. The following diagram gives an overview of the coverage protection for data elements.  The implementation allows for a selection of the amount of coverage of protection across data.  An example that is commonly used is a protection setting of 12 of 16, which means only 12 of 16 data elements are needed to recreate data from a lost disk drive.

Vendors with products that use FEC/erasure codes include Amplidata, Cleversafe, and EMC Isilon and Atmos. Each uses a slightly different implementation, but they are all a form of dispersal and error correction.

The main reason to use erasure codes is for protection from multiple failures. This means multiple drives in a disk storage system could fail before data loss would occur. If data is stored at different geographic locations, you can handle having several locations unavailable to respond and still not lose data. This makes erasure codes a good fit for cloud storage.

Other advantages include shorter rebuild times after a data element fails and less performance impact during a rebuild. A disadvantage of erasure codes is they could add latency and require more compute power when making small writes.

One of the most potentially valuable benefits from using erasure codes is the reduction in service costs for disk storage systems. Using a protection ratio that has a long-term coverage probability (meaning multiple failures will not occur with the potential to lose data for a long period of time), a storage system may not require a failed device to be replaced over its economic lifespan. This would reduce the service cost. For a vendor, this reduces the amount of warranty reserve.

This form of data protection is not prevalent today and it will take time before a large number of vendors offer it. There are good reasons for using this type of protection and there are circumstances when it is not the best solution. Storage pros should always consider the value it brings to their environment.

(Randy Kerns is Senior Strategist at Evaluator Group, an IT analyst firm).