Synchronization Strategy And Efficiency In The Disaster Recovery System

Data, as the valuable resource of enterprises, its importance has been fully acknowledged by people. If enterprise suffers losses caused by error deletion of business data, or by natural disasters such as earthquake, fire and tsunamis, or by changing important data because of hacker attacks, what will be the consequence? At least, these events would bring chaos to business, or even unimagined property losses. As a result, to find an ideal solution to protect data and business from disaster has been the essential and inevitable issues for the enterprise.Generally speaking, most enterprises still adopt tape-based backup technology. However, disaster recovery capability of this technology is limited because conventional backup uses offline backup through tape storage and tapes are also under uniform management in the same location, so once disasters such as fire, theft and earthquake occurs, these backup tapes would be destructed forever, data will be lost and enterprise may need to pay tremendous cost.There are four level of Disaster Recovery software defined by international standard SHARE 78: offline backup with local backup and local storage; offline backup with local backup and remote storage; online backup of site backup and active mutual-aid backup. The first two come under offline backup category, relying upon local or remote regular tape backup for disaster recovery, but is with considerable limitations, for example, lack of real time capability of data and possibility of data losing between backup windows, etc. The last two use single way or bi-directional remote backup points to conduct remote online backup of local data through network; these two solutions, featured by real-time capability, could avoid the possibility of data losing between backup windows.Many technologies are involved in online backup solution, i.e. technologies of SAN or NAS, real-time remote replication, snapshot and rollback. The real-time remote data replication technology, among others, is the core of DR backup system. It can conduct real time remote data copy to keep redundancy backup, and achieve rapid recovery with help of remote backup when local data is damaged. For more precise data backup, we may use snapshot and rollback technologies to recover damaged data. Snapshot works through taking regular snapshots of remote redundancy data and backup the snapshots in tapes for use of data recovery. Rollback technology uses records in IO log of remote redundancy data to conduct data rollback recovery. Relying on its continuity and consistency, users may recover all previous data as required; obviously it's the best solution available for disaster recovery.