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4 Introduction
ProRAID Manager RAID Management Software is an OS-independent Java Application that
manages Epica systems via an Ethernet connection. This software is provided on a CD
shipped with your Epica system and should be installed on the host system that you will use
to manage the system.
The ProRAID Manager provides end users a friendly Java GUI that makes versatile RAID
functions available to general users. Users can easily plan and operation their RAID by using
ProRAID Manager, and they can simply configure different controller series at the same JAVA
Based Platform.
The ProRAID Manager supports Multi-Node Management. If you have several RAID
subsystems connected to the intranet, you can see all these systems when you login to the
ProRAID Manager. The IP Address section lists the RAID systems connected to the network.
4.1 RAID Concepts
RAID Fundamentals
The basic idea of RAID (Redundant Array of Independent Disks) is to combine multiple
inexpensive disk drives into an array of disk drives to obtain performance, capacity and
reliability that exceeds that of a single large drive. The array of drives appears to the host
computer as a single logical drive.
Five types of array architectures, RAID 1 through RAID 6, were originally defined; each
provides disk fault-tolerance with different compromises in features and performance. In
addition to these five redundant array architectures, it has become popular to refer to a non-
redundant array of disk drives as a RAID 0 arrays.
Disk Striping
Fundamental to RAID technology is striping. This is a method of combining multiple drives
into one logical storage unit. Striping partitions the storage space of each drive into stripes,
which can be as small as one sector (512 bytes) or as large as several megabytes. These
stripes are then interleaved in a rotating sequence, so that the combined space is composed
alternately of stripes from each drive. The specific type of operating environment determines
whether large or small stripes should be used.
Most operating systems today support concurrent disk I/O operations across multiple drives.
However, in order to maximize throughput for the disk subsystem, the I/O load must be
balanced across all the drives so that each drive can be kept busy as much as possible. In a
multiple drive system without striping, the disk I/O load is never perfectly balanced. Some
drives will contain data files that are frequently accessed and some drives will rarely be
accessed.