International Business Machines Corporation

International Business Corporation

Shah Mohammad Islam

Andrew Boyce McNeill, Jr

Bharatkumar Jayantilal Oza

Bruce M Cassidy

Because correct configuration data is essential to the operation of any RAID system, and because multiple copies of the configuration data are kept, not only in the RAID controller itself, but also in each disk drive unit in the configuration, it is imperative that the various copies of the configuration data do not become 'out of synchronization', which means that one or more copies of the configuration data are different from one or more other copies of the configuration data. To maintain synchronization of all copies of the configuration data, the current invention compares the configuration data stored in the RAID controllers' NVRAM to that of the current system, and records any new, non-responding, repositioned or unidentified storage devices in a change list. The identities and the attachment points of any storage devices in the change list are then displayed to the user, and various options for correcting the lack of synchronization are provided by enabling one or more function keys that may be selected by the user. One such function key, an 'accept change' key, causes the configuration data to be modified by changing the current operational state of any non-responding storage device. A 'configuration adjustment' key, when selected by the user, causes the configuration data to be modified to reflect any changes in the attachments points of any repositioned storage deices. An 'import configuration' key causes the configuration data to be changed to correspond to that of an unidentified storage device. And a 'retry' key gives the user an opportunity to rearrange the system and then re-compares the configuration data in the controller to the current system configuration. When the system is operating in un-attended mode, means are disclosed to automatically perform the 'accept change', 'configuration adjustment' and 'import configuration' functions in priority order so long as the 'retry' key has not been enabled. The retry key implies attended operation.

RAID system having a selectable unattended mode of operation with

Because correct configuration data is essential to the operation of any RAID system, and because multiple copies of the configuration data are kept, not only in the RAID controller itself, but also in each disk drive unit in the configuration, it is imperative that the various copies of the configuration data do not become 'out of synchronization', which means that one or more copies of the configuration data are different from one or more other copies of the configuration data. To maintain synchronization of all copies of the configuration data, the current invention compares the configuration data stored in the RAID controller's NVRAM to that of the current system, and records any new, non-responding, repositioned or unidentified storage devices in a change list. The identities and the attachment points of any storage devices in the change list are then displayed to the user, and various options for correcting the lack of synchronization are provided by enabling one or more function keys that may be selected by the user. One such function key, an 'accept change' key, causes the configuration data to be modified by changing the current operational state of any non-responding storage device. A 'configuration adjustment' key, when selected by the user, causes the configuration data to be modified to reflect any changes in the attachments points of any repositioned storage devices. An 'import configuration' key causes the configuration data to be changed to correspond to that of an unidentified storage device. And a 'retry' key gives the user an opportunity to rearrange the system and then re-compares the configuration data in the controller to the current system configuration.

RAID array configuration synchronization at power on

In a data processing system, a redundant array of storage devices is provided for storing data from a host data processing system. When a selected, storage device receives a write command, the selected storage device reads old data from the logical address specified in the write command, and temporarily stores such old data in a buffer. Next, the selected storage device writes new data from the host data processing system to a location specified in the write command. Thereafter, an XOR operation is performed in the selected storage device between the new data and the old data to produce intermediate data. The intermediate data is then transferred to a second storage device within the array. Within the second storage device, old parity data is read from the media in the second storage device and placed in a buffer. Next, an XOR operation is performed in the second storage device between the intermediate data and the old parity data to produce new parity data. Finally, such new parity data is written in the second storage device. Commands for reading data, writing data, performing XOR operations, and transferring data are all generated and executed within the storage devices which comprise the redundant array of storage devices.

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Cary, NC, United States of America

Shah Mohammad Islam