Adaptec RAID 2100S Software User's Manual

Also see for 2100S - SCSI RAID Controller: Installation guide Installation guide Quick start guide Installation guide Installation guide

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Adaptec RAID 2100S Software User's Manual Manual pdf 93 page image

3-48Storage ManagerRunning a Verify ProcessRunning a manual Verify for a RAID array ensures that theredundant information contained in the array is consistent.Note: Data inconsistencies should not occur under normalconditions. However, a power failure that interrupts anarray write operation can cause inconsistencies. Making thedata consistent again through the Verify function does notensure that the new consistent data is the correct data.This operation is performed by the RAID controller concurrent withnormal system operation and requires no user or host computerintervention.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 comparedsector by sector to ensure that both drives contain identicaldata. 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 no impacton the host CPU, system I/O performance can be affected due toincreased demand on controller resources. If this is a concern, usethe Background Task Priority feature to assign a lower-level priorityto 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.