Symantec Corporation

Emc IP Holding Company LLC

Dharmesh Shah

Anurag Agarwal

Petros Efstathopoulos

Thomas Alan Bean

Srikanth S Mahabalarao

Sameer Lokray

Taher Vohra

Fanglu Guo

Gopal Sharma

Abhay Kumar Singh

Rajeev Bharadhwaj

Ronald Steinke

Bruce Robert Montague

Ashish Puri

Neelakandan Panchaksharam

Nitin Madan

Srikant Sharma

Gurbir Singh Dhaliwal

Nagaraj Kalmala

Kevin Butler

Srikanth Sm

Grizel Lopez

Ankur Arora

Sureshbabu Basavayya

Implementations are provided herein for the use of multiple threads in concurrently restriping files by maintaining multiple cursors for a single file. The cursors can be stored and tracked on disk in a mirrored data structure ('MDS') extension block also referred to as a Cursor Extension Block. During a restripe operation, individual cursors stored in the delta-block portion of the MDS extension block will be updated using delta operations of a file system. The operating system kernel can maintain an in-memory version of the delta-block portion of the MDS extension block as well. The Cursor Extension Block associated with a file can store data representing the ending logical cluster number of the cursor, the current logical cluster number of the cursor, and a current cursor count for a file.

Multiple concurrent cursors for file repair

A host validation system runs on a portable storage device, and protects data stored thereon from unauthorized access by host computers. The system identifies a host to which the portable device is coupled, for example by using the host's TPM. This can further comprise identifying the host's current configuration. The system uses the identification and configuration information to verify whether the host is approved to access data stored on the portable device. The system provides the host a level of data access responsive to this verification. This can involve denying all data access to the host, or providing at least some access to data stored on the portable device, for example based on a stored access policy specifying levels of access to provide to specific hosts with specific configurations.

Host validation mechanism for preserving integrity of portable storage data

Various embodiments of a system and method for restoring a plurality of files previously deleted from a volume are described. For each respective file of the plurality of deleted files, the method may operate to determine a time at which the respective file was last modified and a time at which the respective file was deleted. These times define a respective recovery time window for the respective file. The method may further comprise determining a particular point in time that is within the recovery time windows for two or more of the plurality of deleted files. A temporary version of the volume as it existed at the particular point in time may be created, and each file of the two or more files may be restored to the volume from the temporary version of the volume.

System and method for efficiently restoring a plurality of deleted files to a file system volume

Techniques for epoch pipelining are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method for epoch pipelining comprising the steps of beginning a first epoch, determining for one or more pages of memory if the pages of memory are likely to be modified in a subsequent epoch, performing a first operation on the pages of memory that are likely to be modified in a subsequent epoch, beginning a second epoch, subsequent to the first epoch, performing a second operation on the pages of memory that are not likely to be modified in a subsequent epoch, and ending the first epoch, wherein the first operation and the second operation are dissimilar.

Techniques for epoch pipelining

A method and apparatus for synchronizing time within a data protection system is described. In one embodiment, the method includes processing input/output activity information associated with at least one client computer, wherein the input/output activity information comprises at least one local client timestamp, determining at least one server timestamp for the at least one local client timestamp and modifying the input/output activity information with the at least one server timestamp.

Method and apparatus for providing time synchronization in a data protection system

A system and method for efficiently reducing a number of duplicate blocks of stored data. A file server both removes duplicate data and prevents duplicate data from being stored in the shared storage. A sampling rate may be used to determine which fingerprints, or hash values, are stored in an index. The sampling rate may be modified in response to changes in characteristics of the system, such as a change in the shared storage size, a change in a utilization of the shared storage, a change in the size of the storage unit, and reaching a threshold corresponding to utilization of the index. Also, a small cache may be maintained for holding fingerprint and pointer pair values prefetched from the shared storage. Each prefetched pair may be associated with data corresponding to a previous hit in the index. The association may be related to spatial locality, temporal locality, or otherwise.

Progressive sampling for deduplication indexing

Techniques for improving dirty page logging are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method for memory logging comprising the steps of determining for one or more pages of memory if the pages of memory are likely to be modified in a subsequent epoch, performing a first operation on the pages of memory that are likely to be modified in a subsequent epoch, and performing a second operation on the pages of memory that are not likely to be modified in a subsequent epoch, wherein the first operation and the second operation are dissimilar.

Techniques for improving dirty page logging

Method and apparatus for transactional fault tolerance in a client-server system is described. In one example, output data generated by execution of a service on a primary server during a current epoch between a first checkpoint and a second checkpoint is buffered. A copy of an execution context of the primary server is established on a secondary server in response to the second checkpoint. The output data as buffered is released from the primary server in response to establishment of the copy of the execution context on the secondary server.

Method and apparatus for transactional fault tolerance in a client-server system

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San Jose, CA, United States of America

Dharmesh Shah