Installation guide

Chapter 1. Introduction
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1.1.3 Instant Availability/Background
Initialization RAID 0 and RAID 1 volume set can be used immediately after the
creation. But the RAID 3 and 5 volume sets must be initialized to generate the
parity. In the Normal Initialization, the initialization proceeds as a background
task, the volume set is fully accessible for system reads and writes. The
operating system can instantly access to the newly created arrays without
requiring a reboot and waiting the initialization complete. Furthermore, the RAID
volume set is also protected against a single disk failure while initialing. In Fast
Initialization, the initialization proceeds must be completed before the volume
set ready for system accesses.
1.1.4 Online Array Roaming/Offline RAID set
The RAID subsystem stores configuration information on the disk drives It can
protect the configuration settings in the case of a disk drive or controller failure.
Array roaming allows the administrators the ability to move a completely RAID
set to another system without losing RAID configuration and data on that RAID
set. If a server fails to work, the RAID set disk drives can be moved to another
server and inserted in any order.
1.1.5 Online Capacity Expansion
Online Capacity Expansion makes it possible to add one or more physical drives
to a volume set, while the server is in operation, eliminating the need to store
and restore after reconfiguring the RAID set. When disks are added to a RAID
set, unused capacity is added to the end of the RAID set. Data on the existing
volume sets residing on that RAID set is redistributed evenly across all the disks.
A contiguous block of unused capacity is made available on the RAID set. The
unused capacity can create additional volume set. The expansion process is
illustrated in the following figure.
The RAID subsystem controller redistributes the original volume set over the
original and newly added disks, using the same fault-tolerance configuration.
The unused capacity on the expanded RAID set can then be used to create an
additional volume set, with a different fault tolerance setting if user needs to
change.
Disk0 40GB Disk1 40GB Disk2 40GB
Free Space = 40GB
Volume 1 = 40GB (D: )
Volume 0 = 40GB (C: )
Array-A 120GB
Before Array Expansion