Emc IP Holding Company LLC

Emc Corporation

Jia Zhai

Yingchao Zhou

Jun Guo

Wengang Wang

William C Davenport

Philippe Armangau

Sen Zhang

Jean-Pierre Bono

Ivan Bassov

Walter Forrester

Christopher Alan Seibel

Sitaram D Pawar

Kumar Kanteti

William K McGrath

Changxin Liu

The present disclosure relates to a method and apparatus for a file system, the file system comprising at least a first logical storage area and a second logical storage area, a logical block of the first logical storage area and that of the second logical storage area being different in size, and in response to a request for creating a file, selecting a logical storage area for storing the file from the at least first logical storage area and second logical storage area; and storing the file in the selected logical storage area. According to the above various embodiments of the present invention, a direct and effective way may be used to support variable-length block size in a file system, without increasing metadata and positioning overheads.

Method and apparatus for file system

A method is provided for storing files in a filesystem of a data storage system. The method includes (a) storing data of each file of a set of files of the filesystem in a set of data allocation units (AUs) of the filesystem on the data storage system, each data AU of the set of data AUs having a common data AU size, and (b) storing metadata pertaining to each file of the set of files in a set of metadata AUs of the filesystem on the data storage system, each metadata AU of the set of metadata AUs having a common metadata AU size, the common data AU size being larger than the common metadata AU size. A computerized apparatus and a computer program product are also provided for performing a method similar to that described above.

Filesystem storing file data in larger units than used for metadata

A method is used in managing replication of file systems. Metadata of a set of slices of a file system is updated upon performing an operation on a slice of the file system. The file system includes the set of slices. The metadata of the set of slices is used for recovering the file system.

Managing replication of file systems

A method is used in managing I/O requests in file systems. A first and second I/O requests are received. The first I/O request is directed to a first portion of a file and the second I/O request is directed to a second portion of the file. Respective first portions of the first and second I/O requests are performed concurrently. Respective second portions of the first and second I/O requests are performed concurrently. Execution of the second I/O request starts before execution of the first I/O request finishes.

Managing I/O requests in file systems

Techniques are provided involving combining several concurrent changes into one consistent condensed transaction within a metadata transaction log using an accumulation list that can be processed to generate a single transaction which may be quickly stored in the metadata transaction log. The improved techniques thus reduce latencies for later concurrent changes and save space within the metadata transaction log.

Combining transactions in a metadata transaction log

A technique performs a host write operation on behalf of a host computer. The technique involves receiving a write request from the host computer, and providing a data write command and a zero write command to backend storage in response to the write request from the host computer. The backend storage maintains a file on behalf of the host computer. Additionally, the data write command includes host data to be written to the file. Furthermore, the zero write command defines a field of zeroes to be written to the file. The technique further involves sending an acknowledgement to the host computer, the acknowledgement serving as a response to the write request from the host computer.

Fast-zeroing in a file system

For automatically committing a file of a file system to a WORM committed state when the file has not been modified for a certain period of time, a file server maintains a list of file identifiers and periodically scans the list to check whether or not the certain period of time has expired for each file on the list. If so, the file is committed to the WORM state. The file server also enforces an in-place lock in response to a client request to modify or delete a file when the certain period of time is found to have expired for the file. A minimum modify time and a maximum modified time are included in each entry of the list of file identifiers in order to skip entries and to reclaim memory of entries during the periodic scan.

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Beijing, China

Jia Zhai