Netapp, Inc.

Amber M Palekar

Szu-Wen Kuo

Stephen Wu

Mardiros Z Chakalian

Rahul Khona

Cindy Zheng

Ashish Prakash

Devang Kundanlal Shah

Jeffrey Pfau

Asynchronous snapshot invalidation techniques are described. According to various such techniques, an enhanced file handle structure may be defined that includes a snapshot generation ID that is to comprise a value that singularly identifies a snapshot performed at a particular point in time. In some embodiments, when a snapshot ID assigned to that snapshot is reused at a subsequent point in time, a different snapshot generation ID may be assigned to that subsequent snapshot. With respect to an in-core cache, the differing snapshot generation IDs may eliminate unacceptable ambiguity regarding respective file information sets corresponding to the initial and subsequent snapshots sharing the same snapshot ID. As a result, obsolete file information sets may be cleared from the in-core cache asynchronously, enabling improved performance. The embodiments are not limited in this context.

Techniques for asynchronous snapshot invalidation

A system and method for deferring an invalidation walk-through of a volume in memory and a later invalidation walk-through of inodes the volume are described herein. Node A may store volume information for one or more volumes to memory including inodes of the volume storing data for the volume. Node A performs a primary procedure that may include removing volumes from the memory, such as a procedure that transfers ownership of the volumes to node B. Removing a volume from memory comprises removing its volume information from memory. Node A performs an invalidation deferment procedure that marks each volume as stale for preventing data of the volumes to be served and sends a completion message to node B which begins serving data of the volume. After node B begins serving data of the volume, node A performs an invalidation walk-through procedure to remove inodes of the volume from memory.

System and method for invalidation walk-through of inodes

System and method for deferring invalidation of inodes of a volume during volume invalidation

Many applications and computing environments allow users to migrate data from a source object to a target object (e.g., a file may be cut/pasted, copied, etc.). It may be advantageous to provide users with access to the data (e.g., migrated data at the target object and/or data that has yet to be migrated from the source object) before all of the data is completely migrated (e.g., a user may otherwise have to wait hours for a 2 TB file to be copied between various data volumes). Accordingly, as provided herein, migration of a source object to a target object may be declared as completed, even though the target object may not comprise all of the data that is to be migrated. In this way, an I/O request may be satisfied based upon migrated data within the target object and/or data, not yet migrated, retrieved on-demand from the source object.

On-demand operations

Described are methods and apparatus for reducing latency of read and write requests for a set of storage system sites having a shared data set. An owner site may directly write to the shared data set and contains current data regarding the shared data set. The remote sites may experience substantial latency when accessing the shared data set stored at the owner site. Synchronizing and caching methods may reduce overall read latency experienced at remote sites by periodically transmitting images of the shared data set to the remote sites. Also, a migration method may be used to change ownership of the shared data set from a current owner site (that may be receiving a relatively low number of read/write requests) to a new owner site (that may be receiving a relatively high number of read/write requests) to reduce the overall read and write latency experienced in the sites.

Growing community of inventors

Sunnyvale, CA, United States of America

Amber M Palekar