Adaptec SCSI RAID 2010S Software User's Manual

Also see for 2010S - SCSI RAID Storage Controller: Installation guide

Contents

Adaptec SCSI RAID 2010S Software User's Manual Manual pdf 85 page image

3-44Adaptec Storage Management Software User’s GuideNote: Data inconsistencies should not occur under normalconditions. However, a power failure that interrupts an arraywrite operation can cause inconsistencies. Making the dataconsistent again through the Verify function does not ensurethat the new consistent data is the correct data.This operation is performed by the RAID controller concurrentwith normal system operation and requires no user or hostcomputer intervention.To start data verification on an array, select Verify in the ArrayGroup Information window.If any inconsistencies in the data redundancy are found, they aremade consistent.■ For RAID 1 arrays, the mirrored drive pairs are compared sectorby sector to ensure that both drives contain identical data.■ For RAID 5 arrays, parity is recalculated and checked againstthe stored parity information.■ For RAID 0, only a disk media ECC check is performed.Running Verify on an array that is in a degraded state can result insignificantly reduced I/O performance. Although there is noimpact on the host CPU, system I/O performance can be affecteddue to increased demand on controller resources. If this is aconcern, use the Background Task Priority feature to assign alower-level priority to background processes.Background Task PriorityYou can run a rebuild or verification operation without taking anarray offline. These operations are performed as background taskson the RAID controller and are transparent to the host operatingsystem. However, the controller interleaves I/O from the operatingsystem with I/O from the background task and this can affectsystem performance.