Avago Technologies 3ware 9650SE-12ML (Channel) - Manual (Page 170)

Maintaining Units
158 3ware SAS/SATA RAID Software User Guide, Version 9.5.1
Background Tasks
Background tasks are maintenance tasks that help maintain the integrity of
your drives and data. These tasks include
• Initialization of units
• Verification of units
• Rebuilds when units have become degraded
• Migration of an on-line RAID from one RAID configuration to another
• Self-tests
You can set up your system so that these tasks occur as they are needed, or
you can create schedules so that they occur during non-peak times.
Background tasks can have an effect on performance, so using a schedule can
minimize the impact.
This section includes the following topics related to background tasks:
• About Initialization
• About Verification
• Starting a Verify Manually
• Rebuilding Units
• Cancelling a Rebuild and Restarting It with a Different Drive
• Setting Background Task Rate
• Background Task Prioritization
• Scheduling Background Tasks
• Viewing Current Task Schedules
• Turning On or Off Use of a Rebuild/Migrate Task Schedule
• Removing a Task Slot from a Schedule
• Adding a New Task Schedule Slot
• Selecting Self-tests to be Performed
Although the migration of a unit is handled as a background task, initiating it
is similar to creating a new unit. For details, see “Changing An Existing
Configuration by Migrating” on page 128.
About Initialization
For 3ware SATA RAID controllers, initialize means to put the redundant data
on the drives of redundant units into a known state so that data can be
recovered in the event of a disk drive failure. This is sometimes referred to as
background initialization or resynching, and does not erase user data.