Summary
This technical report provides an overview of Change Block Tracking (CBT), which records the blocks of a storage object that have been modified by input/output operations. The document outlines the functionality of CBT, emphasizing that it logs which areas of the storage object were written without tracking the specific data changes. The report explains how CBT is utilized in backup processes, particularly in conjunction with snapshot technologies, to enhance backup efficiency by identifying changed blocks between snapshots. It details the operational requirements for effective CBT implementation, including the necessity for fast hooks or filters to minimize performance degradation during production I/O. Additionally, the report discusses the components of CBT, such as persistent records and the importance of capturing all I/O paths to maintain data integrity. Various scenarios affecting CBT, including device identification and reboot processes, are also examined to illustrate the practical considerations in its application.
