International Business Machines Corporation

Other

Robert J Curran

Frank Bernhard Schmuck

Roger Lee Haskin

James Christopher Wyllie

Kuei-Yu Wang-Knop

Zvi Yosef Yehudai

John Michael Marberg

Irit Loy

Boaz Shumeli

Wayne A Sawdon

Boaz Shmueli

Radha R Kandadai

Sibylle Schaller

Carlos Francisco Fuente

Kalyan Chakravarthy Gunda

Douglas J Griffith

Soumitra Sarkar

Yi Zhou

Theodore Brian Vojnovich

Shah Mohammad Rezaul Islam

Felipe Knop

Myung Mun Bae

Thomas K Clark

Sudhir Gurunandan Rao

William A Kish

Wolfgang Mueller-Friedt

Anthony J Zlotek

Daniel Lloyd McNabb

Donald L Hey

Demetrios K Michalaros

Roy C Heidinger

Provided are a system, method, and computer program product for controlling access to a shared storage system in communication with at least one cluster of host nodes. Cluster membership metadata is stored in a storage independent from the shared storage for at least one cluster. The cluster membership metadata is updated in response to an inclusion or exclusion request from a requesting host node comprising one of the host nodes identifying at least one other host node to include or exclude from a cluster. Access to at least one storage volume in the shared storage system is managed in response to the updating of the cluster membership metadata for the inclusion or exclusion request.

Controlling access to a shared storage system

Winter fish traps and methods of using the same are disclosed. A method of trapping fish is provided that includes locating a substantially immobile group of fish in a body of water, providing a semi-rigid water-permeable trap having a bottom opening, lowering the trap opening over the group of fish onto a bottom surface of the body of water to trap the group of fish, remotely operating a semi-rigid door to cover the trap opening while the fish trap is resting on the bottom surface, and retrieving the fish trap from the body of water.

Winter fish traps and methods of using the same

A method for data access in a multinode, shared storage data processing environment is provided by enhancing the file locking mechanism structure so as to permit nodes not normally designated as metadata controller nodes to fulfill that function for limited times thus at least temporarily eliminating the need for continual node-to-node coordination. This is particularly advantageous in the access and transfer of large files such as video files or files containing complex visualization data.

Parallel metadata service in storage area network environment

The acquisition of a lock among nodes of a divided cluster is disclosed. A method is performable by each of at least one node of the cluster. A node waits for a delay corresponding to its identifier. The node asserts intent to acquire the lock by writing its identifier to X and Y variables where another node has failed to acquire the lock. The node waits for another node to acquire the lock where the other node has written to X, and proceeds where Y remains equal to its own identifier. The node waits for another node to acquire the lock where the other node has written to a Z variable, and writes its own identifier to Z and proceeds where the other node has failed. The node writes a value to Y indicating that it is acquiring the lock, and maintains acquisition by periodically writing to Z.

Lock acquisition among nodes of divided cluster

A storage gateway is employed as part of a security enhancing protocol in a data processing system which includes at least one metadata controller node and at least one application node which is granted a time limited access to files in a shared storage system. The gateway is provided with information as to data blocks to which access is to be allowed and also with information concerning the duration of special access granted to a requesting application node. This insures that metadata cannot be improperly used, changed or corrupted by users operating on an application node.

File level security for a metadata controller in a storage area network

File system restoration is made more flexible through the use of indicators of individual file restoration status throughout the restoration process. Such indicators are particularly useful in the restoration of large file systems where, for example, the number of files may range upwards of several hundred million. Since file system restoration for large systems takes such a relatively long time, the present invention provides various degrees of individual file access even as the restoration process is being carried out. During file system restoration times, file access may be full or limited to a file's attributes. Most advantageously, the present invention is capable of providing full, dynamically driven (on-demand) file access even during file system restoration operations.

Rapid restoration of file system usage in very large file systems

In a cluster of computing nodes having shared access to one or more volumes of data storage using a parallel file system, a method for managing the data storage includes selecting a first one of the nodes to serve as a session manager node, and selecting a second one of the nodes to serve as a session node for a data management application. A session of the data management application is created on the session node by sending a message from the session node to the session manager node, causing the session manager node to distribute information regarding the session among the nodes in the cluster. Responsive to the information distributed by the session manager node, events are received at the session node from the nodes in the cluster for processing by the data management application.

Data management application programming interface session management for a parallel file system

File system backups are carried out by first generating a list of inodes including associated inode numbers in inode number order that have changed since the last backup operation. A table which has file names and inode numbers for all of the files currently in the file system is also generated. This list is sorted by inode number and the table and list are merged to provide a structure for determining which files are to be backed up. This means that relevant inodes and file names are now provided in a single entity. It is also noted that the structure that results from the merge operation is particularly suitable for being read in blocks which thus permits the backup operation to be carried out in parallel. The task of backing up files is also preferably partitioned by file size or other criteria as opposed to being partitioned simply by the number of files assigned to be backed up by any one processor in a distributed or parallel data processing system.

Parallel high speed backup for a storage area network (SAN) file system

In a cluster of computing nodes having shared access to one or more file systems in data storage using parallel file system software, a method for managing the data storage includes initiating a session of a data management application on a first one of the nodes, while running a user application on a second one of the nodes. A request is submitted to the parallel file system software by the user application on the second node to mount one of the file systems in the data storage. A mount event message is sent from the second node to the first node responsive to the request, for processing by the data management application on the first node. When the file system is to be unmounted, preunmount and unmount events are sent for processing by the data management application on the first node.

Data management application programming interface handling mount on multiple nodes in a parallel file system

The present invention is directed to a method for controlling file access in a multinode, shared storage, data processing system in which a one set of nodes is capable of acting as metadata controllers and a second set of nodes are tuned for running user applications. By providing two kinds of locks operative at the file level of granularity, a mechanism is produced which permits application programs to also run on their set of metadata controller nodes. One of the locks permits read and write access to existing data blocks but precludes operations such as file deletion or file truncation. The other lock is of lower authority and permits metadata controller nodes, which can provide time limited permissions to the application nodes, to withhold locks which authorize access when requests for access are made from application nodes.

Mechanism for running parallel application programs on metadata controller nodes

In a cluster of computing nodes having shared access to one or more volumes of data storage using a parallel file system, a method for managing the data storage includes initiating a session of a data management application on a first one of the nodes, while running a user application on a second one of the nodes. A request is submitted to the parallel file system by the user application on the second node to perform a file operation on a file in one of the volumes of data storage. A data management event message is sent from the second node to the first node responsive to the request, for processing by the data management application on the first node.

Data management application programming interface for a parallel file system

A method is provided for continuing node operations in quorum-based protocols. This is particularly valuable in the situation in which a group of nodes includes only two nodes and in which communications to a node is lost. Provision is made for adding additional status indications to each node indicating whether or not it is enabled for single-node quorum operation. Provision is also made for identifying one node as a primary node and another node as a secondary node for time-out response purposes.

Support for single-node quorum in a two-node nodeset for a shared disk parallel file system

A method is provided for limiting access to disks and files in the event of a system partitioning occurring as the result of a node failure in a data distributed processing system in which files are shared amongst a plurality of independently running nodes. The nodes in the system are provided with limited duration leases which permit data access and which have to be periodically renewed. Each partition is also associated with a quorum which is also a necessary element in providing access at proper times. The lease and quorum concepts work together to insure that recovery operations do not occur until recovery is possible. The lease concept thus is also seen as further operating in close cooperation with the quorum concept to prevent long delays in the recovery process that could otherwise occur.

Program support for disk fencing in a shared disk parallel file system across storage area network

This invention provides a defragmentation utility that works on-line in parallel with other file system activities. Thus, it avoids making the file system unavailable for periods of time which would, if not for this invention, slow down data communication exchange and the execution of other tasks dependent upon the data. In particular, this invention, steps through all of the valid inodes finding each of the fragments. The defragmentation engine decides which fragments must remain in their current location and which fragments should migrate to another disk block sub-block location. Since the data blocks span across multiple disks, for each valid disk of the file system a set of disk blocks are constructed that are chosen to be filled, herein called plates. When the plates become full or reach a certain fullness, they are removed from the set and replaced by other disk blocks. When a disk block is removed from the plate set, it is moved to a &ldquo;done&rdquo; list as it is considered &ldquo;full&rdquo;. While a disk block is in the done list the fragments that belong to that block are not allowed to migrate. Thus, a defragmentation utility that works on-line, avoids locking data structures for long periods of time, is memory efficient, uses sub-blocks for fragment analysis and migration as well as minimizes data movements has been summarized. This utility thereby provides a transparent defragmentation function that operates in the background seamlessly with other system file operations.

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West Hurley, NY, United States of America

Robert J Curran