Oracle International Corporation

William Bridge

David Brower

Sashikanth Chandrasekaran

Roger J Bamford

Wilson Wai Shun Chan

Vinay H Srihari

Neil MacNaughton

Juan R Loaiza

Steven Wertheimer

James Aubrey Williams

Gregory Pongracz

Angelo Pruscino

J William Lee

Wilson Wai Chan

Terry N Hayes

Patricia C Grewell

Hans Karten

Richard L Long

Thomas V Sepez

Patrick Ritto

Neil Macnaughton

Amit Ganesh

Tirthankar Lahiri

Bipul Sinha

Mark Charles Ramacher

Dmitry Mikhailovich Potapov

Alok Pareek

Arvind Nithrakashyap

Wei Ming Hu

Madhusudan Krishnapuram

Wanli Yang

Francisco Sanchez

Alexander Hwang

Shen-Ban Meng

Cornelius G Doherty

Yuri Sharonin

Thomas Sepez

An elector is provided using shared storage to allow a cluster of participant nodes to gracefully convert failed voters to non-voters until there are only two voters. The cluster can then tolerate the failure of either of those two remaining participant nodes. A tiny amount of shared storage is used as a voter without an object store. This results in a cluster with only one running node that is an exclusive leader. An exclusive leader is then the only participant node that is a voter, and the exclusive leader can commit log records without replicating them to any other members of the cluster. When there is an exclusive leader, there is only one remaining node with a current copy of the object store.

Tolerating server failures in a consensus protocol down to one surviving server using shared storage as a voter

Techniques are provided for managing caches in a system with multiple caches that may contain different copies of the same data item. Specifically, techniques are provided for coordinating the write-to-disk operations performed on such data items to ensure that older versions of the data item are not written over newer versions, and to reduce the amount of processing required to recover after a failure. Various approaches are provided in which a master is used to coordinate with the multiple caches to cause a data item to be written to persistent storage. Techniques are also provided for transferring data items and locks associated with the data items from one node to another.

Methods to perform disk writes in a distributed shared disk system needing consistency across failures

Systems, methodologies, components, and other embodiments associated with controlling access to a storage device are described. One example system embodiment comprises an access controller configured to control access requests to the storage device by metering access to data within a first region within the storage device and by allowing unmetered access to data within a second region within the storage device.

Access controller for storage devices

Techniques are provided for managing caches in a system with multiple caches that may contain different copies of the same data item. Specifically, techniques are provided for coordinating the write-to-disk operations performed on such data items to ensure that older versions of the data item are not written over newer versions, and to reduce the amount of processing required to recover after a failure. Various approaches are provided in which a master is used to coordinate with the multiple caches to cause a data item to be written to persistent storage. Techniques are also provided for managing checkpoints associated with the caches, where the checkpoints are used to determine the position at which to begin processing recovery logs in the event of a failure.

Managing checkpoint queues in a multiple node system

A method and apparatus for creating a target database on a target platform based on a source database on a source platform is provided. A target database is created on the target platform based on data, metadata (for example, data in the system tablespace and control files), and external objects (for example, password files and externally stored tables) comprised within the source database. Data and metadata stored in tablespaces of the source database are converted to the format compatible with the target platform. The conversion of the data and metadata may be performed either at the source database or the target database. Redo information and undo information of the source database are not copied from the source database to the target database. Certain files, e.g., a password files, and links to externally stored object may be recreated on the target database.

Cross-platform transportable database

An apparatus and method for accessing a data item from a storage system having a plurality of data storage devices are disclosed. I/O operation requests are submitted to multiple data storage devices for each data item to be accessed. The I/O operation requests are issued to copies of the data items that reside on a plurality of data storage devices. More I/O operation requests are submitted than the number of data items that are to be accessed, written, or updated.

Method and apparatus for managing data access and storage of data located on multiple storage devices

Methods are provided for communicating with and regulating access to a storage system contained within a file system. Storage access keys are used to communicate to the file system changes in location of data stored in the storage system. Fence keys are used to regulate access to the storage system.

Storage access keys

A system and methods for simulating the performance (e.g., miss rate) of one or more caches. A cache simulator comprises a segmented list of buffers, with each buffer configured to store a data identifier and an identifier of the buffer's segment. Data references, which may be copied from an operational cache, are applied to the list to conduct the simulation. Initial estimates of each cache's miss rate include the number of references that missed all segments of the list plus the hits in all segments not part of the cache. A correction factor is generated from the ratio of actual misses incurred by the operational cache to the estimated misses for a simulated cache of the same size as the operational cache. Final predictions are generated by multiplying the initial estimates by the correction factor. The size of the operational cache may be dynamically adjusted based on the final predictions.

System and method for predicting cache performance

An approach for efficiently managing logical volumes of data includes subdividing logical volumes of data into relatively small pieces that are spread over several physical disks. When a determination is made that a particular disk drive is to store more than one piece of a volume, a plurality of pieces of the volume are selected to be stored on the particular disk drive based at least in part on how far apart the pieces are within an address space of the volume. In response to an addition of one or more new drives to a system that contains a plurality of disk drives, at least a piece of each of the plurality of volumes may be moved from a drive of the plurality of disk drives to at least one of the one or more new drives.

Method and system for managing storage systems containing multiple data storage devices

A method and mechanism for implementing variable sized extents for a logical volume or file is disclosed. Instead of using extents which all have the same size to form a logical volume, a logical volume includes extents having different extent sizes. A relatively small extent size is used for extents allocated for the first portion of a logical volume, which increases to a larger extent size for extents allocated to a second portion of the logical volume, which again increase one or more times for extents allocated for later portions of the logical volume.

Method and system for implementing variable sized extents

Growing community of inventors

Alameda, CA, United States of America

William Bridge