Hitachi HF-W2000 30, User Manual

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9. RAID1
9-1
CHAPTER 9 RAID1
9.1 What Is RAID1?
This chapter explains how to use the RAID1 functions peculiar to HJ-2035vwxyD (D Model)
of HF-W2000 Model 35. References to the “Equipment” in this chapter only apply to
D Model of HF-W2000 Model 35. It is only an HDD that Equipment adopts.
NOTICE

Although this Equipment featuring RAID1 is more reliable than general
systems, it is still prone to the loss of data in the HDDs. Not only a machine
failure but also an unexpected power failure or an operation error may cause
data to be lost for good. To prevent such loss of data, implement scheduled
data backup in daily operation. Also, protect the power source from
undesirable interruptions by such means as UPS.

This Equipment is evaluated based on the specific HDD models authorized by
the Manufacturer. Replace only with specific HDD models authorized by the
Manufacturer. Otherwise, the existing data in the HDD may be lost. Also,
always observe the recommended replacement interval for HDDs (Section 5.3,
“Replacement of Consumable Parts”).

Since each Equipment has its own RAID1 configuration information (e.g.,
serial number), you cannot swap HDDs even between two units of this
Equipment. If you dare, the stored data in the newly installed HDD will be
erased with automatic RAID1 rebuilding process due to inconsistency of the
RAID1 configuration information. If you own multiple units of this Equipment,
manage use and inventory of HDDs so that they are not inadvertently mixed.

Each Equipment contains uniquely assigned HDD serial numbers in its own
RAID1 configuration information. Accordingly, if you create a copy of the
existing HDD without using the RAID1 rebuilding process, the copy will be
recognized new and invalid. This new HDD, if installed in the drive bay, will
not start up the Equipment.

Maintenance of a disk array system requires in-depth knowledge. In case of
an operation error, data in the HDD may be lost.
RAID1 (Redundant Array of Independent Disks Level 1) is a technique commonly known as
mirroring. The controller of the RAID1 divides the HDDs of an array into two groups and
writes the same data to both of them. Reading is performed from one of the groups. If an
HDD in one group should become faulty, the system can read from the corresponding normal
HDD of the other group. Although the Equipment uses two HDDs, the available disk
capacity is that of one HDD due to mirroring.
This Equipment graphically displays the HDD status of RAID1 by means of the built-in RAS
software. For how to use this RAS software, refer to Section 2.8, “RAID Monitoring
Feature” in
HF-W2000 Model 35/30 RAS Features Manual . The display images in this
chapter assume those under Windows® 7.