| Because of the speedy development of integrated circuits , the computer's computation capability takes exponential growth. But the low increase speed of storage devices' (like a disk) I/O, the CPU's computation capability can't match with it ending a bottleneck. At the same time, with the rapid development of nowadays information technology, the size of data storage is gradually up to TB or PB. It's hard to satisfy user needs by purely depend on disk and tape.According to the problem above, it's necessary to design a kind of file storage system which with large volume, high reliability and usability, perfect performance, dynamic extension and easy to maintenance. Through research on NAS and SAN which are two kinds of network storage structure, it puts forward a distributed storage system that bases on soft-RAID technology, this system not only has the merits of NAS and SAN, but also can overcomes their shortcomings.Every storage node stores part of data file and the matching metadata. When a storage node starts up, it will communicate with any other node in the same local area network, and finally gain all the metadata information. As the individual storage node is independent, it improves the system's parallelism and expansibility.Towards hotspot file, referencing the thought of RAID, we can divide a consecutive stream of data into a series of data blocks, the blocks all being of the same size, and write each segment data into different storage node, so the file access speed will be boosted when takes a parallel-access method.For the facility to use the storage system, LDFS file system is designed and realized on the application server, you can operate the system like an ordinary one when it's mounted.Test indicates that the I/O performance of Linux distributed storage system is much better than Samba file system and CIFS, when they access data that in equal size in the same network environment. |
