Modified Data Blocks Driven Snapshots for Disaster Recovery of File Systems for Consistent RTO
In the file system level Disaster Recovery (DR) configurations with asynchronous data replication, synchronized peer snapshots are taken periodically based on Recovery Point Objective (RPO)at local and remote file systems. Once local file system has hit disaster, the remote file system is restored to most recent snapshot for data consistency. The time to restore remote file system contributes to Recovery Time Objective (RTO) which is not consistent and not predictable. In this paper a new efficient procedure is described for taking snapshots based on distinct data blocks modified, defined as “Recovery Data Blocks Objective” (RDBO).In our experiments it is observed that the RTO is linearly proportional to the distinct data blocks modified from most recent snapshot. This helps to accurately and consistently estimate the RTO based on RDBO defined for file systems.
Keywords - RTO, File Systems Recovery Time, Modified Data Blocks Driven Snapshots, Recovery Data Block Objective (RDBO)