HP DL760 HP ProLiant DL760 Generation 2 Server User Guide - Page 146

Installing Hardware Options, Hot-Pluggable Advanced Data Guarding When a disk drive is hot-plugged, although the system is functionally operational, the disk subsystem may no longer be fault tolerant. Fault tolerance will be lost until the removed drive is subsequently replaced and the rebuild operation is completed. This procedure takes several hours, even if the system is not busy while the rebuild is in progress. If another drive in the array should incur an error during the period when fault tolerance is unavailable, a fatal system error could result. If another drive fails during this period, the entire array contents will be lost. IMPORTANT: Perform disk drive replacement during low activity periods whenever possible. In addition, a current valid backup of the logical drives in the array of the drive being replaced should be available even if the drive replacement is being made during server downtime. When replacing hot-plug hard drives in a fault-tolerant configuration, you must follow these guidelines: • Never remove more than one drive at a time. When a drive is replaced, the controller uses data from the other drives in the array to reconstruct data on the replacement drive. If more than one drive is removed, a complete data set is not available to reconstruct data on the replacement drive. • Never remove a working drive when another drive has failed. Drives that have been failed by the controller are indicated by the amber Drive Failure LED on the drive tray. Permanent data loss will occur if a working drive is removed while a failed drive is being replaced. • Never remove a drive while another drive is being rebuilt. The Online LED of a drive will flash green while the drive is being rebuilt. A replaced drive is restored from data stored on the other drives. HP ProLiant DL760 Generation 2 Server User Guide 5-31