3Ware 9550SXU-12 User Guide - Page 179

Background Tasks Notes: If a unit that requires initialization has not previously been initialized, selecting Verify Unit starts initialization. This is because fault-tolerant units cannot be verified until after they are initialized. If the unit is already in a state of rebuild, initialization, or verification, the unit cannot be verified in 3BM. You must boot the system and let the task finish in the background. Rebuilding Units Rebuilding is the process of generating data on a new drive after it is put into service to replace a failed drive in a fault tolerant unit. If a hot spare of the appropriate drive type (SAS or SATA) is specified and a redundant unit degrades, it will be used to automatically replace the failed drive in the redundant unit without intervention on your part. The rebuild process will automatically be launched as a background process at the next scheduled time. If scheduling is turned off, the rebuild process will start almost immediately (within a couple of minutes). If 3DM is running and Email notification is enabled, an event notification will be sent to specified users when the unit degrades and again when the rebuild process is complete. If the Auto Rebuild policy is enabled (see "Setting the Auto Rebuild Policy" on page 91), the firmware will attempt to rebuild a degraded unit with an available drive or a failed drive. If desired, you can manually replace the drive, rescan the controller, and start the rebuild process. Manual rebuilds can be started from either 3BM, CLI, or 3DM, although the rebuild itself only happens when the operating system is running. The rebuild process may take less time if Rapid RAID Recovery has been enabled during unit creation. See "Rapid RAID Recovery" on page 126. Rebuilds on multiple units can take place simultaneously. If multiple drives are faulted in a RAID 10 configuration, the drives are rebuilt simultaneously. In a 4-drive RAID 10 configuration, up to two drives can be rebuilt. In a 6-drive configuration, up to three drives can be rebuilt. In an 8-drive configuration, up to four drives can be rebuilt. In a 12-drive configuration, up to six drives can be rebuilt. Note: If both drives in a RAID 10 mirrored set are faulted, the data is not recoverable. Up to half of the drives in a RAID 10 unit can become defective and still have the user data retained, as long as the failed drives are only half of each mirrored pair. A RAID 5 unit can have one drive fail before becoming inoperable. www.3ware.com 167