Orverview
During and immediately after the Great East Japan Earthquake, many information servers were lost, resulting in the disappearance of resident registry information and medical information, which revealed the vulnerability of the existing storage systems against disaster. This is attributable to the fact that conventional availability has been dependent in many cases on multiplexing at the site (such as RAID technology). Damage to the site itself and long-term power failure caused by tsunamis and fire were not considered. For improved disaster resistance, it is necessary that the system configuration be such that information is stored at more than one site in a geographically distributed fashion and that the system should recover quickly by reconstitution of the surviving information.
