Maintaining Units162 3ware SAS/SATA RAID Software User Guide, Version 9.5.1Background Initialization After Power FailureThe 3ware controller detects and handles power failures, using a mechanismthat ensures that redundant units have consistent data and parity. When aredundant unit is unexpectedly shutdown, there is a possibility some data andparity may be inconsistent. If a unit or sub-unit of a redundant unit is detectedto have been shutdown uncleanly, the unit or sub-unit will change its mode toeither ‘Initializing’ or ‘Verifying.’When the initialization is complete, the unit is guaranteed to be redundantagain. The initialization does not erase user data.This process will take less time if the unit is created with Rapid RAIDRecovery enabled during unit creation. See “Rapid RAID Recovery” onpage 126.About VerificationThe verify feature confirms the validity of redundant data on redundant unitsand performs media scans on non-redundant units.Regular weekly verification is a good idea, as it can provide early warning ofa disk drive problem or failure. This allows you to replace drives before theyfail.You can start a verify manually or regular verification can be doneautomatically by enabling Auto Verify. (See “Starting a Verify Manually” onpage 165 and “Using Auto Verification” on page 164.)During verification, I/O continues normally, but with a slight performanceloss, depending on your verify rate setting. You can adjust how muchverification will slow performance by setting a rate at which it occurs. (See“Setting Background Task Rate” on page 172.) You can also postponeverification until a scheduled time. (See “Scheduling Background Tasks” onpage 173.)Yes RAID 5 with 5 or more disksRAID 6RAID 50 with subunits of 5 or more disksTable 12: Initialization Requirements for Different RAIDConfigurationsInitialization Requiredfor HighestPerformance?RAID Configurations
