Oracle International Corporation

Vmware, Inc.

Emc IP Holding Company LLC

Satish Kumar Kashi Visvanathan

Viggnesh Venugopal

Pooja Sarda

Vikram Singh Bisht

Ilya Langouev

Rahul Ugale

Arun Kandambakkam

Victor Vladimir Golosovker

Ravi Lingappa Shamanna

Parth Singhal

Niharika Salady

Stephen Anthony Fridella

Ashwin Vijayavel

Mahesh Kamat

Sudarsan R Piduri

Michael Zucca

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

Techniques are described for performing different types of restart operations for a file storage replication between a source file system and a target file system in different cloud infrastructure regions. In certain embodiments, the disclosed techniques perform a restart operation to terminate a current cross-region replication by synchronizing resource cleanup operations in the source file system and the target file system, respectively. In other embodiments, disclosed techniques perform a restart operation to allow a customer to reuse the source file system by identifying a restartable base snapshot in the source file system without dependency on the target file system.

End-to-end restartability of cross-region replication using a new replication

Techniques are described for efficient replication and maintaining snapshot data consistency during file storage replication between file systems in different cloud infrastructure regions. In certain embodiments, provenance IDs are used to efficiently identify a starting point (e.g., a base snapshot) for a cross-region replication process, conserve cloud resources while reducing network and IO traffic.

Techniques for efficient replication and recovery

Techniques are described for efficient replication and maintaining snapshot data consistency during file storage replication between file systems in different cloud infrastructure regions. In certain embodiments, snapshot creation and deletion requests that occur during cross-region replications may be temporarily withheld until appropriate times to execute such requests safely, depending on the timing relationship between such requests and cross-region replication cycles.

Techniques for maintaining snapshot data consistency 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.

Techniques for managing overwrites when archiving data in cloud/object storage are provided. In one set of embodiments, a computer system can overwrite a chunk of data residing in cloud/object storage, where the cloud/object storage only guarantees eventual consistency for overwrites, and where the overwriting is associated with a sequence number. Upon overwriting the chunk of data, the computer system create a new instance of a file in the cloud/object storage, where the new instance of the file has a version number corresponding to the sequence number.

Managing overwrites when archiving data in cloud/object storage

According to one set of embodiments, a computer system can receive a request or command to delete a snapshot from among a plurality of snapshots of a dataset, where the plurality of snapshots are stored in cloud/object storage. In response, the computer system can add the snapshot to a batch of pending snapshots to be deleted and can determine whether the size of the batch has reached a threshold. If the size of the batch has not reached the threshold, the computer system return a response to an originator of the request or command indicating that the snapshot has been deleted, without actually deleting the snapshot from the cloud/object storage.

Batch-based deletion of snapshots archived in cloud/object storage

Techniques for archiving data in cloud/object storage using local metadata staging are provided. In one set of embodiments, a computer system residing at an on-premises site comprising on-premises storage can receive a snapshot of a dataset to be archived. The computer system can package data in the snapshot into one or more fixed-size data chunks and upload the one or more fixed-size data chunks to cloud/object storage. Further, concurrently with the packaging and the uploading, the computer system can stage metadata for the snapshot in the on-premises storage. Then, upon uploading all of the data of the snapshot, the computer system can upload the metadata staged in the on-premises storage to the cloud/object storage.

Growing community of inventors

San Jose, CA, United States of America

Satish Kumar Kashi Visvanathan