Lsi Logic Corporation

Marlin J Gwaltney

Rodney A Dekoning

Timothy R Snider

A method for detection of hot-swap of disk drives in a storage subsystem devoid of special circuits for such detection and for buffering of bus signals. Typical prior designs utilize special circuits such as disk drive canisters for physically and electronically connecting the disk drives to the storage subsystem. These canisters provided electronic buffering to reduce or eliminate transient (noise and glitch) signals associated with hot-swap drive removal and insertion. In addition, such canisters provided special purpose circuits to inform storage subsystem control modules that a possible insertion or removal occurred by forcing a reset of the interconnection bus in response to detection of such transient signals. The present invention provides for such detection without need for such complex (e.g., costly) special purpose circuits. Specifically, for example in a RAID subsystem using a SCSI interface to interconnect control modules with disk drives, the methods of the present invention detect a possible removal of a disk drive either by periodically polling the SCSI IDs of the RAID subsystem for changes therein or by resetting the SCSI interface in response to errors in processing I/O activity to a removed disk drive. Other methods of the present invention detect insertion of disk drives, either added disk drives or re-inserted disk drives, by periodically polling the SCSI IDs of the RAID subsystem. The methods of the present invention thereby detect hot-swap disk drive insertion and removal without complex (costly) custom circuits therefor.

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Augusta, KS, United States of America

Marlin J Gwaltney