Symantec Corporation

Veritas Technologies LLC

Ryan Lefevre

Anindya Banerjee

Kedar Shrikrishna Patwardhan

Brad Boyer

Mitul Kothari

Balemurughan Kumaresan

Raghupathi Malige

Sunil Kumar Tekkatte Subramanya

Meher Shah

Daniel Fillingham

Ragupathi Malige

Edwin Frederick Menze, Iii

Various methods and systems for optimizing cache consistency are disclosed. For example, one method involves writing data to a file during a write transaction. The file is stored in a persistent storage device and cached in a non-volatile storage device. The method determines if an in-memory flag associated with the persistent storage device set. If the in-memory flag is not set, the method increases a generation count associated with the persistent storage device before a write transaction is performed on the file. The method then sets the in-memory flag before performing the write transaction on the file. In other examples, the method involves using a persistent flag associated with the non-volatile storage device to maintain cache consistency during a data freeze related to the taking of a snapshot by synchronizing generation counts associated with the persistent storage device and the non-volatile storage device.

Cache consistency optimization

Various systems and methods for inhibiting a modified block of data from being written to an underlying persistent storage device are disclosed. A cache is maintained by a file system and the cache is implemented to temporarily cache portions of application data for an application. The application data for the application is stored on the underlying persistent storage device. Metadata is accessed if it is detected that a block of data in the cache has been modified. The metadata indicates that the block of data is not needed for the integrity of the application. In response to the metadata, the modified block of data is inhibited from being written to the underlying persistent storage device.

Caching temporary data in solid state storage devices

Techniques for evicting cached files may be realized as a method including: maintaining a file system cache storing selected files from a file storage; for files that are above a threshold size, selectively storing chunks of the files; for each file that is stored, associating an access bit and a size bit with that file; for each file that is stored selectively as file chunks, associating an access bitmap to the file having an access bit associated with each file chunk; when a file is accessed, setting the access bit associated with the file and file chunk to indicate recent access; at set intervals, periodically clearing the access bits to not indicate recent access; and carrying out a cache eviction process comprising evicting at least one file or file chunk associated with an access bit that does not indicate recent access.

Techniques for evicting cached files

A method of reading data from a partitioned directory incident to a serialized process. A first read and an offset value are received. A first data block in a modeled fully partitioned directory is identified based on the offset value and a predetermined number of entries associated with a buffer. It is determined whether the first data block in the fully partitioned directory is present in the actual partitioned directory. Zeros are written in the buffer if the first data block in the fully partitioned directory is not present in the actual partitioned directory otherwise the first data block associated with the actual partitioned directory is written to the buffer. A second data block is similarly read by a second read operation and written. The second data block is associated with a second subdirectory, selected based on a horizontal node traversal at a node level of said first subdirectory.

Method and system for efficiently reading a partitioned directory incident to a serialized process

Storage systems and methods are presented. In one embodiment, a storage reclamation method comprises performing a potential reclamation identification process, wherein the potential reclamation identification process includes determining if there is the potential for reclaiming storage resources; performing a reclamation process, wherein reclamation is performed on storage resources identified by the potential reclamation identification process as being eligible for reclamation, and wherein the storage resources correspond to free space associated with a data file; and performing a valid free space indication process, wherein a valid free space indication process includes forwarding a valid free space indication recognizable to an application as a valid free space indication when the application attempts to direct a read to the storage spaces reclaimed by the reclamation process.

Data storage reclamation systems and methods

A client without direct access to a server performs commands on files of the server's file system, wherein the file system is made available by a network file system protocol. Calls to access the file system on the server are filtered. A call is identified that is passed a parameter comprising a filename with an identifiable filename extension. The identifiable filename extension is interpreted as indicating that the identified call was made as part of an attempt to execute an operation that is overloaded with a different command. It is determined, from the identifiable filename extension, which command is to be executed instead of the operation. Once the command to be executed is determined, the filename extension is removed from the parameter, and the determined command is executed instead of the overloaded operation.

Growing community of inventors

Sunnyvale, CA, United States of America

Ryan Lefevre