Hitachi HF-W2000 30, User Manual

Page: 190 / 227

10. SOFTWARE RAID1
10-1
CHAPTER 10 SOFTWARE RAID1
10.1 Overview of Software RAID1
This chapter explains how to use the software RAID function of the equipment model HJ-
2030****B (B model).
In this chapter, “the Equipment” means HJ-2030****B (B model). HDDs are the only drives
the Equipment uses for the software RAID function, and therefore, a drive is denoted as
“HDD” in the following explanation.
NOTICE

The Equipment features RAID1 and is highly reliable compared to a system
with a conventional configuration. Nonetheless, the data stored on the HDDs
may be lost depending on the type of the failure. In addition to equipment
failure data can also be lost by power failure and human mistakes during
operation. Should such situation occur, the data cannot be recovered. In order
to prevent data loss, make it a routine to save your data and establish a
systematic way of backup. In addition, increase the reliability of power supply
by, for example, using a UPS.

The Equipment is evaluated under the assumption that the HDD models
specified by HITACHI are used. When you replace an HDD, use the HDD
models specified by HITACHI. Otherwise, the data stored in the HDDs may be
lost. Stick to the recommended replacement cycle when you replace an HDD.
(See Section 5.3, “Replacement of Consumable Parts”.)

The Equipment manages the unique serial number of each HDD (each HDD
has a different serial number) as part of RAID1 configuration information.
Therefore, if you copy the contents of an HDD to another HDD without using
the rebuild function of the software RAID1 construction utility, the HDD with
the copied contents is recognized as an invalid medium. Even if you mount the
HDD to a drive bay, the Equipment will not start.

Maintenance of a disk array system requires a high level of expertise. Should
any mistakes be made during the maintenance work, data stored in the HDDs
may be lost.
RAID1 (Redundant Array of Independent Disks Level 1) is a technology generally referred
to as “mirroring”. The software RAID1 does not use a RAID controller (hardware) for
mirroring but uses software to implement RAID1. Should either one of the HDD pair fail,
you can read out data from the other working HDD. RAID1 uses two HDDs but the available
capacity is the capacity of one HDD.
The Equipment graphically shows the status of HDDs used for software RAID1 using the
RAS software. For information about how to use the RAS software, refer to Section 2.8,
“RAID Monitor Function” in the “
HF-W2000 Model 35/30 RAS Features Manual ”. Screen
images of the hardware status window in this chapter are examples from Windows® 7.
The Equipment comes with the software RAID1 construction utility “Software RAID1 For