In-memory databases - the next big thing?

Ditching hard drives allows for dramatically faster real-time data analysis.

SAP has released its Hana “in-memory” computing appliance in New Zealand, which it hopes will revolutionise real-time data crunching. A number of companies are working on "in-memory" servers, helping to solidify the technology's "next big thing" status, but SAP is among the first off the blocks with getting product to market, and the first to push it locally.

The guts of it is that today’s databases are usually stored on hard disk drives.
But memory chips have now got cheap enough that even a huge database can be stored on them – allowing for dramatically faster data analysis. 
In SAP's hero case study a consumer packaged goods company was able to reduce its point-of-sale data set, consisting of 460 billion records, from 120 Terabytes in a traditional relational database to 40 Terabytes in teh more streamlined all-memory environment. It claimed real-time data analysis was 20 times faster.
The company's setup included 10 Hana blade servers, with 500GB of memory per server, plus 2 Terabytes of solid state memory.
SAP’s NZ country manager, Graeme Riley, admitted HANA is not perfect. 
The problem is that any data held in-memory will disappear if someone trips over a power.
"This data, managed in memory, is volatile and in the event of a server failure, that data is lost from that memory," a rep for SAP acknowledged.

"However, data held in memory by Hana is backed up by a persistence layer that logs transactions to a non-volatile technology (such as solid state drives) on the Hana server. This allows the data to be restored in the event of a power outage or other similar disruption, and ensures that customer data is never lost."
So far SAP has sold 30 or 40 HANA boxes worldwide, with no takers so far in New Zealand.
But in Japan, one of the customers is the Nomura Institute, which is using Hana to track the GPS feeds from 12,000 Tokyo taxis – with the ultimate aim that they’re real-time movements are so co-ordinated that electric cabs with a three-hour battery life could be controlled by the SAP system.
In New Zealand, Mr Riley sees potential for Hana with the increasing deployment of smart meters, which typically send usage data back to a power company every 30 minutes.