High performance journaling for replication and continuous data protection

摘要

Technologies are described herein for high-performance and space efficient journaling mechanisms. A journal queue can buffer incoming I/O operations. The queue can be read by a journal write module. The journal write module can form metadata headers to store into the journal along with each I/O operation. Compound metadata headers may be formed for multiple I/O operations and the combination of multiple I/O operations may be efficiently stored to the journal as one journal write. Multiple journal entries may be written into the journal in parallel while maintaining the sequential ordering of the journal. A queue depth threshold can be established for determining if journal entries should be combined into compound entries or not. Multiple concurrent readers can support continuous data protection, and various data replication features. Each reader can be represented as a reader pointer and a journal writer can invalidate reader pointers when related data is overwritten.