Aiwa Co., Ltd.

Aiwa Raid Technology, Inc.

Gerald Edward Smith

Adam Wayne Weiner

A method for reconfiguration of a disk drive array is provided. For the method of the present invention, an array controller in a disk drive array examines the original configuration of the disk drive array (the source configuration) and the desired configuration (the destination configuration). Based on this examination, the array controller determines if the reconfiguration process may be optimized. To optimize the reconfiguration process, the array controller determines if a combination of changes to system parameters and possible rebuilding operations can replace the migration process. If this is possible, the reconfiguration process is modified to eliminate data migration. Otherwise, data migration is performed. In this way, the present invention provides a method that dramatically increases the speed of reconfiguration for some source and destination configurations.

Method for reconfiguration of RAID data storage systems

A RAID system that uses non-volatile random access memory (NVRAM) to greatly reduce the chance of loss of data due to an AC power failure. This RAID system has two write modes. In a normal write mode, a host computer receives a write confirmation once an array controller receives data from the host computer. In a safe write mode, however, the array controller copies to NVRAM all data received from the host computer for writing to disk drives. In this safe write mode, the array controller sends the write confirmation to the host computer only after storing the data in NVRAM. To switch appropriately between the normal and safe write modes, the array controller polls a power-out flag provided by a UPS (uninterruptable power supply) to determine whether there has been an AC power failure. The array controller switches between the two write modes depending on the status of the power-out flag.

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Boynton Beach, FL, United States of America

Gerald Edward Smith