Design and Practice of File Backup System Taking Advantage of Remotely Distributed Campuses

摘要

We present a file backup system designed for a university on the basis of its experiences with the 2011 east Japan earthquake. This system has two levels of security: (1) The web site for public relations and the e-mail systems for communications that will work continuously even in the case of commercial power failure. (2) The personal computer systems that will be down during power failure but will restart working without any loss of data as soon as the power supply is back. The former has been implemented by employing a private cloud computing platform and a public one in combination. To the latter, the same cloud-computing approach was not applicable because it causes latency and extra cost of communications in the normal time to keep the frequently accessed data in a cloud storage. Fortunately, this particular university has three campuses so far away that one may be destroyed by a single disaster but the other two will survive. Taking advantage of the remote campuses, we designed and implemented a file storage system that keeps the original copy on-premise in a campus and its backup copy in one of the other two campuses. Its operations have shown that the communication traffic among the campuses increased only by half in order to keep the data safe against natural disasters.