HP ProLiant 1500 SMART-2DH Array Controller Reference Guide - Page 171

G-3 In any RAID 1 logical drive on the SMART-2DH Controller having N physical drives in the array (not including spare drives), the first N/2 physical drives are normally mirrored in consecutive order to the second N/2 physical drives. When determining the order, number each drive in the array by increasing IDs on the first SCSI bus, followed likewise by drives on the second SCSI bus. s Can sustain a single drive failure. The logical drive will be in a "regenerating" condition if one drive is failed. s Will be in a "failed" condition if more than one drive is failed. s Will be in a "rebuilding" condition if a previously failed drive has been replaced and the replacement drive is rebuilding. The volume may also be in a "rebuilding" condition following a drive failure if a spare drive was previously assigned and is rebuilding. Spare Drives In the event of a drive failure, if a spare drive is assigned and available, the spare drive acts as an immediate replacement for the failed drive. Data is automatically reconstructed from the remaining drive(s) in the volume and written to the spare drive via the Automatic Data Recovery process. Once the spare drive is completely built, the logical drive is again running at full fault tolerance, and is then able to sustain another subsequent drive failure. Note, however, that if another drive were to fail before the spare drive is completely built, the spare drive cannot prevent failure of the entire logical drive. Also note that it is possible for non-correctable disk errors to prevent completion of the Automatic Data Recovery process (discussed below). SMART-2DH Array Controller Reference Guide Writer: Pamela King Project: SMART-2DH Array Controller Reference Guide Comments: 295469-002 File Name: N-APPG.DOC Last Saved On: 2/27/98 12:09 PM COMPAQ CONFIDENTIAL - NEED TO KNOW REQUIRED