Emc Corporation

Eyal Zimran

Christopher H Stacey

Sorin Faibish

Jason Glasgow

Christian J Chuba

Uday K Gupta

Xiaoye Jiang

Stephen A Fridella

Ivan Basov

Jiannan Zheng

James Theodore Compton

Stephen A Rago

Augustine Amegadzie

Jerald W Gross

Mary Walker

Accordingly a method and interface allows an attribute data base used by an Information Manager to be quickly populated and accurately maintained. A single Bulk Attribute Retrieval Request triggers the primary storage device to collect object attribute information. The method allows for selective collection of objects and attributes by providing filters and attribute lists in the Requests. The Request may be used to provide an incremental scan with appropriate time stamp filtering. In addition, the size of the results can be controlled by the IM by eliminating attributes that are not of interest to the IM. The Request is advantageously issued over a FileMover interface, which is an HTTP connection, and encoded in XML, allowing the IM to easily customize the Request as desired.

Method and apparatus for performing bulk file system attribute retrieval

A protected file is retained in secondary storage for a retention period, and a corresponding stub file is retained in primary storage for the retention period. The stub file retains attributes of the file indicating a location of the file data in the secondary storage and indicting that the stub file is to be retained for the retention period. A system administrator may instruct a primary file server that a secondary file server supports retention based protection and it is desired to protect stub files corresponding to protected files that are migrated to the secondary file server. The primary file server may request the secondary file server to return a protection status of the file after migration. This enables automatic policy-based migration to both file level retention (FLR) and non-FLR retention protected secondary storage from diverse applications accessing FLR or non-FLR files in the primary storage.

Primary stub file retention and secondary retention coordination in a hierarchical storage system

Embodiments of the present invention are directed to techniques for selecting a data path over which to exchange information between a client device and a storage system by making a selection between a file system server (NAS) data path type (a first data path type) and a direct (SAN) data path type (a second data path type) based on one or more adjustable path selection factors and/or information regarding components of the computer system. For example, a data path may be selected based on a likelihood that requested information will be in a cache of a file system server and/or any other suitable path selection factor.

Selection of a data path based on the likelihood that requested information is in a cache

A hierarchical storage system is constructed from file servers and a policy engine server by building upon a file migration service. Offline attributes are added to file system inodes in a primary file server, file system parameters are added in the primary server, an offline read access method field is added to a connection database, and the primary file server is programmed to use these attributes and parameters for selecting a particular method (such as a partial read migration or a pass through read method) for read access to an offline file. In this fashion, the primary file server is provided with flexibility for selecting a particular one of a number of migration methods depending on various conditions, in order to improve the trade-off between the cost of storage and delay in file access.

Selection of migration methods including partial read restore in distributed storage management

Embodiments of the present invention are directed to techniques for selecting a data path over which to exchange information between a client device and a storage system by making a selection between a file system server (NAS) data path type (a first data path type) and a direct (SAN) data path type (a second data path type) based on one or more adjustable path selection factors and/or information regarding components of the computer system. For example, a data path may be selected based on a type of an input/output operation to be executed (i.e., whether the operation is a read operation or write operation) and/or any other suitable path selection factor.

Selection of a data path based on operation type

Embodiments of the present invention are directed to techniques for selecting a data path over which to exchange information between a client device and a storage system by making a selection between a file system server (NAS) data path type (a first data path type) and a direct (SAN) data path type (a second data path type) based on one or more adjustable path selection factors and/or information regarding components of the computer system. For example, a data path may be selected based on one or more performance characteristics of a computer system in which a path selection module is acting and/or any other suitable path selection factor.

Selection of a data path based on one or more performance characteristics of a computer system

A read-write snapshot copy facility is constructed from a hierarchical storage management facility. The read-write snapshot copy file system initially comprises stub files pointing to the files in a read-only snapshot copy file system. When an application writes to a file in the read-write snapshot copy, the read-write snapshot copy facility migrates a copy of the file to replace the stub file, and then writes to the migrated file. Because the read-write snapshot copy facility references the files in the read-only snapshot file system in a network namespace using standard protocols such as NFS or CIFS, the read-write snapshot copy facility permits referencing of distributed read-only snapshot file systems in an open (heterogeneous) network environment, and the read-write snapshot copy is scalable by linking the read-write snapshot copy facility to multiple file servers containing read-only snapshot file systems.

Distributed open writable snapshot copy facility using file migration policies

A hierarchical storage system includes file servers and a policy engine server. Offline attributes are added to file system inodes in a primary file server, file system parameters are added in the primary server, offline read and write access method fields are added to a connection database, and the primary file server uses these attributes and parameters for selecting a particular read method or write method for access to an offline file or section of an offline file. The write methods follow a 'write recall full' policy, a 'pass-through write' policy, a &#x201c;pass-through multi-version&#x201d; policy, or a &#x201c;directory write pass-through&#x201d; policy. The pass-through multi-version policy results in a new offline version of a file each time that a client opens and writes to a multi-version file. The directory write pass-through policy results in a new offline file when a file is created within a write pass-through directory.

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London, United Kingdom

Eyal Zimran