The design and implementation of an extensible network backup system in realtime

• Authors: Nishimura Satoshi;Sano Mutsuo;Ikeda Katsuo
• Venue: Proceedings of the 3rd International Conference on Ubiquitous Information Management and Communication
• Year: 2009

This paper proposes a backup system based on mirroring filesystem "GMFS." GMFS has been developed to mirror data in realtime on the filesystem layer. The GMFS is a stackable filesystem which flexibly mirrors without changing the existing environment by operating as a wrapper of other filesystems. Because the conventional mirroring technology utilizes the mirroring function on the device layer or needs a special filesystem, the allocation of the disk and the specific format of the filesystem are needed, and so the disk design is fixed. Therefore, the conventional mirroring technology cannot adjust when the mirroring function not assumed will be needed later. In this situation, the mechanism that adds the mirroring function without changing the existing disk design is necessary. The GMFS conducts the operation of other filesystems transparently, thereby users need not be aware of the GMFS. The conventional filesystem looks as if it performs mirroring data by itself. GMFS can therefore add the function that mirrors in realtime without destroying the existing environment. GMFS uses NFS which is a typical network file system to communicate with an existing environment. The throughput of reading and writing has been improved by adopting the method to call system function of NFS from the inside of the filesystem. We developed this filesystem, and evaluated the performance from the viewpoint of throughput and system call speed and CPU loads. As a result, it was shown that there was no problem in the viewpoint of the performance compared with the conventional filesystem, and the throughput of the read and write of GMFS was 2.0 times faster than conventional mirroring filesystem.