HP 70 HP StorageWorks 70 Modular Smart Array Enclosure User Guide (434893-003, - Page 37
Time required for a rebuild, Failure of another drive during rebuild
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or rebuild. If fault tolerance is compromised, this data cannot be reconstructed and is likely to be permanently lost. If another drive in the array fails while fault tolerance is unavailable during rebuild, a fatal system error may occur, and all data on the array is then lost. In exceptional cases, however, failure of another drive need not lead to a fatal system error. These exceptions include: • Failure after activation of a spare drive. • Failure of a drive that is not mirrored to any other failed drives (in a RAID 1+0 configuration). • Failure of a second drive in a RAID 6 with ADG configuration. Time required for a rebuild The time required for a rebuild varies considerably, depending on several factors: • The priority that the rebuild is given over normal I/O operations (you can change the priority setting by using ACU) • The amount of I/O activity during the rebuild operation • The rotational speed of the disk drives • The availability of drive cache • The brand, model, and age of the drives • The amount of unused capacity on the drives • The number of drives in the array (for RAID 5 and RAID 6 with ADG) Allow approximately 15 minutes per gigabyte for the rebuild process to be completed. This figure is conservative, and newer drive models usually require less time to rebuild. System performance is affected during the rebuild, and the system is unprotected against further drive failure until the rebuild has finished. Therefore, replace drives during periods of low activity when possible. CAUTION: If the Online LED of the replacement drive stops blinking and the amber fault LED glows, or if other drive LEDs in the array go out, the replacement drive has failed and is producing unrecoverable disk errors. Remove and replace the failed replacement drive. When automatic data recovery has finished, the online LED of the replacement drive stops blinking and begins to glow steadily. Failure of another drive during rebuild If a non-correctable read error occurs on another physical drive in the array during the rebuild process, the Online LED of the replacement drive stops blinking and the rebuild abnormally terminates. If this situation occurs, restart the server. The system may temporarily become operational long enough to allow recovery of unsaved data. In any case, locate the faulty drive, replace it, and restore data from backup. Drive failure in a NetWare environment Use CPQONLIN to identify and monitor drive failure status in a NetWare environment. 70 Modular Smart Array User Guide 37