IBM 86655RY Hardware Maintenance Manual - Page 197

Automatically rebuilding the defunct drive The ServeRAID controller will rebuild a defunct drive automatically when all of the following conditions exist: • The physical drive that failed is part of a redundant RAID logical drive. See "Reference information" on page 192 for more information on data redundancy. • A hot-spare or standby hot-spare drive with a capacity equal to or greater than the capacity of the defunct drive is available the moment the drive fails. - When multiple hot-spare drives are available, the ServeRAID controller searches for a hot-spare drive of the appropriate size. The smallest drive that meets this requirement enters the Rebuild state. - If no hot-spare or standby hot-spare drives are available, the rebuild operation will start the moment you replace the defective drive. Note: If you physically replace the drive and the new drive does not appear in the Physical Drives branch of the Main Tree, you must scan for new or removed Ready drives. • No rebuild, synchronization, logical-drive migration, or RAID level-5E compression/decompression operation is in process. Software and physical replacement When the ServeRAID controller communicates with the hard disk drive and receives an unexpected response, the controller will mark the drive defunct in order to avoid any potential data loss. For example, this could occur in the event of a power loss to any of the components in the SCSI ServeRAID subsystem. In this case, the ServeRAID controller will err on the side of safety and will no longer write to that drive, although the drive may not be defective in any way. It is recommended to use a software replace to recover data when multiple Defunct (DDD) drives occur. In this situation, you may lose data on drives that are not actually defective if you run a normal rebuild process. Perform a software replace or a physical replace according to the following criteria: • A software replace is recommended when trying to recover data when multiple Defunct (DDD) drives occur. Warning: If you use the wrong order when you attempt a software replace, your data will be corrupted. • Do not perform a software replace for a single Defunct (DDD) drive. All single defunct drives should be physically replaced. • Replace the Defunct (DHS) drive physically if a Defunct (DDD) drive has been replaced by an HSP. The drive must be replaced physically to ensure that a good HSP drive is present in the system. Using ServeRAID Manager to determine the correct order to software replace The following lists describe the correct order to software replace under two conditions: operating system is accessible and operating system is not accessible. When the operating system is accessible, to determine the correct order to software replace follow the following steps: 1. Using ServeRAID Manager, note the hard disk drive(s) that are defunct. Installing and configuring ServeRAID controllers 187