3Ware 9550SXU-12 User Guide - Page 185

Scheduling Background Tasks Background Task Prioritization Although migration tasks follow the same schedule as rebuild and initialization tasks, they are always given the highest priority because of the controller and disk resources required during migration. Once a unit is put into the migration state, it must be allowed to complete the process. While migrating, rebuilds or verifies to the unit are not permitted. Rebuilding preempts verify operations. If a unit requires rebuilding, that process will take place before the unit is verified. Controllers can work on multiple units at the same time. This means that if you have both a redundant unit and a non-redundant unit, the verification of the redundant unit and the media scan of the non-redundant unit will occur at the same time. Scheduling Background Tasks You can set up scheduling windows for when background tasks occur so that routine maintenance of storage media occurs when it will be least likely to interfere with day-to-day work on the system (peak I/O times). By creating and using schedules, you can specify when active rebuilding, migrating, verifying, and testing of units should occur. For example, you might wish these tasks to occur at 2AM each day, or on weekends. Note: Initialization follows the rebuild/migrate schedule. The default setting for both is to ignore the schedule. Rebuild/migrate, verify, and self-test tasks are scheduled separately, but in a very similar way. You can perform the following scheduling tasks: • Viewing Current Task Schedules • Turning On or Off Use of a Rebuild/Migrate Task Schedule • Selecting Advanced or Basic Verify Schedules • Removing a Task Slot from a Schedule • Adding a New Task Schedule Slot • Selecting Self-tests to be Performed Tip: If you want to change a task schedule window, you first remove the schedule item and then add it back with the desired day, time, and duration. www.3ware.com 173