Emc Corporation

International Business Machines Corporation

Dov Bulka

Manoj Nair

Martin J Presler-Marshall

Ashok Ramakrishnan

Shon Boggs

Ken Collins

Phillip Ray Hinton, Jr

Neel Mehta

Eric Wagner

Methods, systems, and computer program products for optimizing resource allocation in a host-based replication environment are disclosed. According to one aspect, the subject matter described herein includes a method for optimizing resource allocation in a host-based replication environment. The method includes assigning a weight to each of a multiple of file system entities to be replicated. The method also includes creating a list of available transfer agents for replicating file system entities, the list having first and second ends and the list including at least one entry representing each transfer agent. The method also includes alternating between starting from the first end of the list and moving through the list until the second end of the list is reached and starting from the second end of the list and moving through the list until the first end of the list is reached, and, while moving through the list, assigning in order of weight each of the file system entities to the transfer agent represented by the current entry in the list.

Methods, systems, and computer program products for optimizing resource allocation in a host-based replication environment

A method and system are described for reducing search for data in a directory scheme employing hash tables. The method involves compacting directory entries in a manner in which the directory entries will gradually migrate and concentrate at the highest level hash tables which coincide with early blocks in a hash table sequence representing the directory.

Method and system of compacting sparse directories in a file system

Methods and systems of searching a file access system for a requested file. One embodiment includes allocating memory for directory cache and buffer cache. The directory cache stores a directory file layout. The directory cache is searched for a requested file, and a pointer points to where the name of the requested file is stored in the buffer cache. If the directory cache does not exist, then the embodiment reverts to conventional file access methods. The directory cache may store only selected directories. The selected directories may be chosen based upon at least one of the number of files in a directory, the frequency of use or access, or other user-specified criteria.

File access system

This invention provides a negative cache management system and method for controlling valid and invalid memory component identifiers, and, thereby, accelerates performance of relatively high speed memory components, including hardware and software systems, that operate with storage devices. This invention includes (a) logic to check the cache to determine if a received memory component identifier is invalid, (b) logic to add the invalid memory component identifier to the cache, such as adding a file identifier to the cache when a search in a directory for a file name is unsuccessful, (c) logic to monitor new memory component identifiers being created and to remove an entry from the invalid list if that file identifier later becomes valid, (d) logic to monitor memory component identifiers being deleted or moved and to add an entry from the invalid list if that file identifier becomes invalid, (e) logic to manage the most frequently used invalid memory component identifiers, and (f) logic to manage the most recently used invalid memory component identifiers.

Method and system for identifying memory component identifiers associated with data

Timestamp updating systems, methods and computer program products for data processing systems provide a timestamp register that stores a current value of a timestamp and a time thread that repeatedly generates a current value of a timestamp and stores the current value of a timestamp so generated in the timestamp register. When the timestamp is being stored in the register, applications are locked from accessing the register. At other times, however, the applications may obtain the timestamp from the timestamp register, rather than accessing the system clock and formatting a timestamp each time a timestamp is required. A semaphore may be used to lock and unlock the timestamp register. Alternatively, a buffer is provided including a plurality of registers, each of which stores a timestamp therein. A time thread repeatedly generates a current value of a timestamp from the system clock and stores the current value of a timestamp so generated in a selected one of the registers. Applications can concurrently obtain a current value of a timestamp from the remaining ones of the registers.

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Raleigh, NC, United States of America

Dov Bulka