Oracle International Corporation

Viggnesh Venugopal

Satish Kumar Kashi Visvanathan

Vikram Singh Bisht

Victor Vladimir Golosovker

Ravi Lingappa Shamanna

Stephen Anthony Fridella

Ashwin Vijayavel

Sudarsan R Piduri

Haoran Qi

John McClain

Techniques are described for enabling concurrent cross-region replications and garbage collection while maintaining consistency and data integrity among file systems. In some embodiments, techniques for garbage collection fencing utilize a system-level garbage fencing key (GC fencing key) and one or more job-level GC fencing keys in a source file system that perform one or more cross-region replications with one or more target file systems, one replication and one job-level GC fencing key per target file system. In some embodiments, one job-level GC fencing key in a source file system and one job-level GC fencing key in a source file system together provide garbage fencing for a cross-region replication. In certain embodiments, the metadata information in a GC fencing key can inform, instruct, or be used to configure garbage collectors to skip garbage collection for a range of snapshots in a file system.

Techniques for maintaining snapshot key consistency involving garbage collection during file system cross-region replication

Techniques are described for a hierarchical caching mechanism enabling efficient cross-region replications. In some embodiments, replication-related information (e.g., key-value pairs) is stored in a particular layout in a binary tree (B-tree) of a file system for replication processing. A hierarchy of caches storing a first type of information (e.g., crypto keys associated with iNodes) may be arranged to match the particular layout in the B-tree to enable efficient parallel processing of a second type of information (e.g., files, file data, or symbolic links), where the replication-related information in the B-tree is partitioned into multiple key ranges for parallel processing. In some embodiments, the caches in different hierarchies may be shared by different parallel-processing key ranges and replication jobs in a file system.

Techniques for efficient encryption and decryption during file system cross-region replication

Novel techniques are described for performing hierarchical key management involving an end-to-end file storage replication between different cloud infrastructure regions. The novel hierarchical key management comprises three different keys, a first security key for the source region, a session key, valid only for a session, for the transfer of data between two different regions, and a second security key for the target region. Novel techniques are also described for using different file keys for different files of a file system in each region.

Hierarchical key management for cross-region replication

Novel techniques for end-to-end file storage replication and security between file systems in different cloud infrastructure regions are disclosed herein. In one embodiment, a file storage service generates deltas between snapshots in a source file system, and transfers the deltas and associated data through a high-throughput object storage to recreate a new snapshot in a target file system located in a different region during disaster recovery. The file storage service utilizes novel techniques to achieve scalable, reliable, and restartable end-to-end replication. Novel techniques are also described to ensure a secure transfer of information and consistency during the end-to-end replication.

Scalable and secure cross region and optimized file system delta transfer for cloud scale

Novel techniques are described for maintaining file consistency between different cloud infrastructure regions during cross-region file storage replication. The novel techniques comprise upon detecting a file deletion status (i.e., a file directory entry version marked as deletion) in a source file system during a replication cycle, retrieving file name from a valid file directory entry of a prior snapshot to construct a temporary file directory entry containing necessary information for a target file system to reconstruct a duplicate file directory entry version marked as deletion. The temporary file directory entry is transferred from the source file system to the target file system during the same replication cycle.

Techniques for maintaining file consistency during file system cross-region replication

Techniques are described for checkpointing multiple key ranges in parallel and concurrently during file storage replications between file systems in different cloud infrastructure regions. In certain embodiments, multiple range threads processing multiple key ranges, one thread per key range, create checkpoints for their respective key ranges in parallel and concurrently after processing a per-determined number of B-tree keys. In certain embodiments, upon encountering a failure event, either a system crash or a thread failure, each thread restarts its B-tree key processing from a B-tree key after the most recent checkpoint.

Techniques for replication checkpointing during disaster recovery

Techniques are described for partitioning B-tree keys of file systems into key ranges for parallel processing in delta generation during file storage replications between file systems in different cloud infrastructure regions. In certain embodiments, a delta generation processing for cross-region replication may utilize a key-range splitting mechanism involving a recursive algorithm that partitions B-tree keys of a source file system into roughly equal-size key ranges. All the partitioned key ranges may be processed in parallel and concurrently by different processing threads, one thread per key range, to improve the performance of the delta generation and achieve scalability.

Partitioning mechanism for parallel processing in delta generation

Techniques are described for ensuring end-to-end fair-share resource utilization during cross-region replication. In certain embodiments, a fair-share architecture is used for communication among pipeline stages performing a cross-region replication between different cloud infrastructure regions. Cross-region replication-related jobs are distributed evenly from a pipeline stage into a temporary buffer in the fair-share architecture, and then further distributed evenly form the fair-share architecture to parallel running threads of next pipeline stage for execute. Techniques for static and dynamic resource allocations are also disclosed.

Techniques for resource utilization in replication pipeline processing

Techniques are described for checkpointing multiple key ranges in parallel and concurrently during file storage replications between file systems in different cloud infrastructure regions. In certain embodiments, multiple range threads processing multiple key ranges, one thread per key range, create checkpoints for their respective key ranges in parallel and concurrently after processing a per-determined number of B-tree keys. In certain embodiments, each thread requests a lock from a central checkpoint record and takes turns for updating a status byte while continuing processing the B-tree keys in its responsible key range. In certain embodiments, upon encountering a failure event, either a system crash or a thread failure, each thread restarts its B-tree key processing from a B-tree key after the most recent checkpoint.

Growing community of inventors

Santa Clara, CA, United States of America

Viggnesh Venugopal