International Business Machines Corporation

Philip Anthony Richardson

Shah Mohammad Rezaul Islam

Prasenjit Sarkar

Linda Ann Riedle

Vikram Harakere Krishnamurthy

David Carroll Challener

Dean Alan Kalman

Andrew Boyce McNeill, Jr

Bharatkumar Jayantilal Oza

Shah Mohammed Rezaul Islam

Shah Mohammed Islam

The present invention provides a method and system for more efficiently providing a copy of a portion of a source drive of a plurality of drives in a redundant array of inexpensive disks (RAID) data storage system. The portion of the source drive includes a plurality of segments. The method and system include providing the copy of the plurality of segments from the source drive to the target drive. The plurality of segments can be modified during the step of providing the copy. The method and system further include providing another copy of a portion of the plurality of segments that have been modified since the step of providing the copy commenced if a portion of the plurality of segments have been modified since copying commenced.

Method and system for more efficiently providing a copy in a raid data storage system

A method and system for storing data in a redundant array of inexpensive disks (RAID) data storage subsystem is disclosed. The RAID data storage subsystem includes a plurality of drives. The method and system include temporarily storing data in a first portion of the plurality of drives using a first RAID level and relatively permanently storing the data in a second portion the plurality of drives using a second RAID level. The step of relatively permanently storing the data is performed at a time when performance of the system is not substantially affected by storage using the second RAID level. Furthermore, the temporary storing step and the step of storing the data using the second RAID level may be performed throughout operation of the RAID data storage subsystem. Thus, RAID data may be cached using the first RAID level, then relatively permanently stored using the second RAID level.

Method and system for caching data using raid level selection

A method and system for a data storage system to update stored data with received data in a cache associated with the data storage system where the data storage system comprises N data storage drives is provided, where data and calculated parity are striped across the N data storage drives. An associated cache is provided with the data storage system for receiving data. The data in the cache is periodically examined to determine if the data includes all sequential data contained within a complete stripe within the data storage system. Data is fetched from the N data storage drives into the cache and the parity for the stripe is calculated by logically combining the received data in the cache and fetched data from the data storage drives if the cache is determined not to include all sequential data contained within the complete stripe. Alternatively, the parity for the stripe is calculated by logically combining only data within the cache for the stripe, if data in the cache is determined to include all sequential data contained within a complete stripe, thereby minimizing the number of input/output operations required to update data.

Method and system for updating data in a data storage system

A method for migrating data from one level of RAID system to the same or another level of RAID system having the same or a different number of removable and identifiable storage devices and having the same or a different stripe unit size is disclosed. The storage devices can be attached to the system at a number of different attachment points which facilitates replacement or removal of a failed device. The system is represented as a logical media drive. After determining the number of migrations and the direction of migration, a start logical block address and an end logical block address is defined. The migration is performed by moving data from the source physical blocks to the destination physical blocks starting with the physical block corresponding to the start logical block address and continuing to the physical block corresponding to the end logical block address.

Logical drive migration for a raid adapter

Means and method are disclosed for managing data while a RAID system is recovering from a media error. As a media error occurs, the failing storage device is identified and the areas of failure are recorded in non-volatile storage. A data recovery process is then continued so that a maximum amount of data can be recovered even though more than one error has occurred. Areas of failure are recorded in both non-volatile memory on the RAID adapter card and also in reserved areas of remaining storage devices. The storage areas that have been detected to contain media errors are stripe number, stripe unit number and also down to the sector number level of granularity. When the user tries to access data, these records are checked. If there is an entry in the table for a stripe being accessed, the user will receive an error message. Although the user may lose a small portion of the data, the user is only presented with an error message instead of incorrect data. The table can also be checked on write operations. If an entire stripe of data is written successfully and that stripe is found in the table, the entry is removed. When a physical device is moved to another controller, the table is copied from the physical device being moved to the new controllers non-volatile memory so this information is not lost.

Managing defective media in a RAID system

A method and system for providing a backup of a portion of a source drive of a plurality of drives in a redundant array of inexpensive disks (RAID) data storage system is disclosed. The portion of the source includes a plurality of segments. The method and system include associating the source drive with a target drive of the plurality of drives and providing a copy of the plurality of segments on the target drive. The copy is provided such that input to and output from source drive and the target drive are allowed during the step of providing the copy of the plurality of segments.

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Apex, NC, United States of America

Philip Anthony Richardson