Lenovo ThinkServer RD240 MegaRAID SAS Software User Guide - Page 38

Note: During a copyback operation, if the drive group involved in the copyback is deleted because of a virtual drive deletion, the destination drive reverts to an Unconfigured Good state or hot spare state. Order of Precedence - In the following scenarios, rebuild takes precedence over the copyback operation: 1. If a copyback operation is already taking place to a hot spare drive, and any virtual drive on the controller degrades, the copyback operation aborts, and a rebuild starts. The rebuild changes the virtual drive to the optimal state. 2. The rebuild operation takes precedence over the copyback operation when the conditions exist to start both operations. For example: a. Where the hot spare is not configured (or unavailable) in the system. b. There are two drives (both members of virtual drives), with one drive exceeding the SMART error threshold, and the other failed. c. If you add a hot spare (assume a global hot spare) during a copyback operation, the copyback is aborted, and the rebuild operation starts on the hot spare. 2.4.7 Background Initialization Background initialization is a consistency check that is forced when you create a virtual drive. The difference between a background initialization and a consistency check is that a background initialization is forced on new virtual drives. This is an automatic operation that starts 5 minutes after you create the virtual drive. Background initialization is a check for media errors on the drives. It ensures that striped data segments are the same on all drives in a drive group. The default and recommended background initialization rate is 30 percent. Before you change the rebuild rate, you must stop the background initialization or the rate change will not affect the background initialization rate. After you stop background initialization and change the rebuild rate, the rate change takes effect when you restart background initialization. 2-6 Introduction to RAID