Research And Implementation Of Data Disaster Tolerance System On Linux

Considering the current situation of most companies and ministries without data-protecting mechanism, this thesis presents the Data Disaster Tolerance System on Linux, abbreviated to DDT, based on researching the current Disaster Tolerance systems and related technologies. The thesis introduces and discusses the basic concepts, architecture and work flow of DDT system, and focuses on describing key technologies including Remote Replication mechanism, Disaster Recovery mechanism and Snapshot Backup mechanism. In addition, the thesis evaluates DDT system in theory and with experiments.The key technologies which are researched and implemented in DDT system can be summarized as following:First, Module-embedding technology: DDT system embeds the Remote Replication module into Logical Volume Manager in Linux kernel to build Logical Volume Replicator which can intercept the writing requirements and replicate them to the Secondary system. It also embeds the Disaster Recovery module into LVR to build Data Disaster Tolerance system which can deal with disasters effectively.Secondary, Remote Replication mechanism: In order to keep the Data Consistency between Primary system and Secondary system and that in Replication Volume Group and apply in different environments, DDT system supplies users with three replication models of Sync, Async, and Soft-Sync, and designs relevant transportation protocol and Jounal mechanism to ensure that Remote Repication can work normally.Third, Disaster Recovery mechanism: In order to improve the High-Availability, DDT system implements Disaster-Over strategy which selects one available Secondary system to take over Primary system when failures or disasters occur to the system. DDT system also puts forward Full/Fast Disaster-Back strategy which can recover original Primary system according to Secondary system and reuse Primary system to serve the users.Fourth, Snapshot Backup mechanism: DDT system can backup data of Secondary system online or off-line based on the Snapshot technology of LVM, which is the supplement of Remote Backup and can improve the reliability of DDT system.DDT system is a High-reliability and High-availability system software, which embeds Remote Replication mechanism and Disaster Recovery mechanism in the Logical Volume Manager, and combines them with Snapshot Backup mechanism to increase the ability of data disaster tolerance of computer systems. It can be applied in remote data backup, disaster recovery and so on, and it supplies users with an economical, applicable and reliable kind of solution for building Disaster Tolerance system.