Emc Corporation

Emc IP Holding Company LLC

Emc IP Holding Corporation LLC

Gang Ma

Sorin Faibish

James M Pedone, Jr

Xiaoye Jiang

Percy Tzelnic

John Michael Bent

Uresh K Vahalia

Stephen A Fridella

Tao Peng

Jiannan Zheng

Dominique P Cote

Rui Liang

A storage system comprises a shared storage environment that includes a storage array having at least one storage volume shared between first and second host devices. The storage system further comprises a server associated with the storage array, at least first and second clients associated with the respective first and second host devices, and a first block cache arranged between the first client and the storage array. The server is configured to coordinate operations of the first and second clients relating to the storage volume shared between the first and second host devices in a manner that ensures coherency of data stored in the first block cache. The server may comprise a storage block mapping protocol (SBMP) server and the first and second clients may comprise respective SBMP clients. The block cache is illustratively implemented using a VFCache or other type of server flash cache.

Block caching in a shared storage environment

Block caching between a host device client and storage array in a shared storage environment

A cluster file system comprises a plurality of clients and a plurality of servers configured to communicate over a network. A given server of the cluster file system interfaces with an associated storage array, and comprises a block cache and a request translator. The request translator is configured to translate input-output requests in a protocol of the cluster file system to a format suitable for use with the block cache. The cluster file system may more particularly comprise a Lustre file system, and the given server may comprise a metadata server or an object storage server of the Lustre file system. In such an embodiment, the request translator is more particularly configured to translate Lustre client input-output requests directed to the storage array into block input-output requests that are processed by the block cache. The block cache is illustratively implemented using a VFCache or other type of server flash cache.

Cluster file system with server block cache

A storage system comprises a storage array, a network file system configured to communicate with the storage array, a server associated with the network file system, a client configured to communicate over a first path with the network file system via the server and to communicate directly with the storage array over a second path that bypasses the network file system, and a block cache arranged in the second path between the client and the storage array. The server may comprise a multi-path file system (MPFS) server and the client may comprise an MPFS client, with the MPFS server and the MPFS client being configured to communicate using a file mapping protocol. The block cache is illustratively implemented using a VFCache or other type of server flash cache.

Multi-path file system with block cache between client and storage array

Metadata management in a file server or storage network is delegated from a primary data processor to a secondary data processor in order to reduce data traffic between the primary data processor and the secondary data processor. The primary data processor retains responsibility for managing locks upon objects in the file system that it owns, and also retains responsibility for allocation of free blocks and inodes of the file system. By leasing free blocks and inodes to the secondary and granting locks to the secondary, the secondary can perform the other metadata management tasks such as appending blocks to a file, truncating a file, creating a file, and deleting a file.

Delegation of metadata management in a storage system by leasing of free file system blocks from a file system owner

To permit multiple unsynchronized processors to update the file-modification time attribute of a file during concurrent asynchronous writes to the file, a primary processor having a clock manages access to metadata of the file. A number of secondary processors service client request for access to the file. Each secondary processor has a timer. When the primary processor grants a range lock upon the file to a secondary, it returns its clock time (m). Upon receipt, the secondary starts a local timer (t). When the secondary modifies the file data, it determines a file-modification time that is a function of the clock time and the timer interval, such as a sum (m+t). When the secondary receives an updated file-modification time (mp) from the primary, if mp&#x3e;m+t, then the secondary updates the clock time (m) to (mp) and resets its local timer.

Management of the file-modification time attribute in a multi-processor file server system

Delegation of metadata management in a storage system by leasing of free file system blocks and i-nodes from a file system owner

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West Roxbury, MA, United States of America

Gang Ma