Netapp, Inc.

Mardiros Z Chakalian

Stephen Wu

Szu-Wen Kuo

Amber M Palekar

Darrell Gene Suggs

Aswini S Kumar

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

The techniques introduced here provide for a write-back sparse volume cache in a storage system. The write-back sparse volume cache is implemented by a first storage server that is connected to communicate with a second storage server that hosts the origin storage volume. The first storage server receives a write request from a client to write data to the origin storage volume. In response to receiving the write request, the first storage server writes the data to the sparse volume cache maintained by the first storage server and acknowledges to the client a successful write operation. The data is maintained in the sparse volume cache such that the presence of the data in the sparse volume cache is transparent to the client and subsequent requests for the written data are serviced by the first storage server from the sparse volume cache. The data can later be flushed to the origin storage volume.

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San Jose, CA, United States of America

Mardiros Z Chakalian