Adaptec 2100S - SCSI RAID Controller Podręcznik Użytkownika Pobierz pdf (Strona 93)

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Storage Manager

Running a Verify Process

Running a manual Verify for a RAID array ensures that the

redundant information contained in the array is consistent.

Note: Data inconsistencies should not occur under normal

conditions. However, a power failure that interrupts an

array write operation can cause inconsistencies. Making the

data consistent again through the Verify function does not

ensure that the new consistent data is the correct data.

This operation is performed by the RAID controller concurrent with

normal system operation and requires no user or host computer

intervention.

To start data verification on an array, select Verify in the Array

Group Information window.

If any inconsistencies in the data redundancy are found, they are

made consistent.

■ For RAID 1 arrays, the mirrored drive pairs are compared

sector by sector to ensure that both drives contain identical

data.

■ For RAID 5 arrays, parity is recalculated and checked against

the 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 in

significantly reduced I/O performance. Although there is no impact

on the host CPU, system I/O performance can be affected due to

increased demand on controller resources. If this is a concern, use

the Background Task Priority feature to assign a lower-level priority

to background processes.

Background Task Priority

You can run a rebuild or verification operation without taking an

array offline. These operations are performed as background tasks

on the RAID controller and are transparent to the host operating

system. However, the controller interleaves I/O from the operating

system with I/O from the background task and this can affect

system performance.

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Adaptec 2100S - SCSI RAID Controller Podręcznik Użytkownika Strona 93