Areca ARC-5030 Series, Руководство пользователя

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INTRODUCTION
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because it runs as a background task. Auto Reassign Sector
discontinues when the operating system makes a request.
1.5.3 Consistency Check
A consistency check is a process that verifies the integrity of
redundant data. For example, performing a consistency check
of a mirrored drive assures that the data on both drives of the
mirrored pair is exactly the same. To verify RAID 3, 5 or 6 redun-
dancy, a consistency check reads all associated data blocks, com-
putes parity, reads parity, and verifies that the computed parity
matches the read parity.
Consistency checks are very important because they detect and
correct parity errors or bad disk blocks in the drive. A consis-
tency check forces every block on a volume to be read, and any
bad blocks are marked; those blocks are not used again. This is
critical and important because a bad disk block can prevent a disk
rebuild from completing. We strongly recommend that you run
consistency checks on a regular basis—at least once per week.
Note that consistency checks degrade performance, so you should
run them when the system load can tolerate it.
1.6 Data Protection
1.6.1 RECOVERY ROM
The RAID subsystem firmware is stored on the controller flash
ROM and is executed by the I/O processor. The firmware can also
be updated through Ethernet port (if equipped) without the need
to replace any hardware chips. During the controller firmware up -
grade flash process, it is possible for a problem to occur resulting
in corruption of the controller firmware. With our Redundant Flash
image feature, the controller will revert back to the last known
version of firmware and continue operating. This reduces the risk
of system failure due to firmware crash.
1.7 Understanding RAID
RAID is an acronym for Redundant Array of Independent Disks. It
is an array of multiple independent hard disk drives that provides