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Management Software
All RAID controllers come with some sort of software that lets you manage the
controller and its connected arrays and drives. This software can range from very simple
to very complex, depending on the type of controller and the number of features it
supports. Most hardware controllers come with two different software components:
- Controller BIOS Setup Program: This is a hardware-based program that
can be run at boot time in exactly the same way that a motherboard's BIOS setup program operates. By pressing the
appropriate key(s) at the appropriate time during the boot sequence, a special program
contained in a ROM chip on the controller appears on the screen (usually in a text-only
mode) and allows various functions to be performed. This program manages a set of data
contained on the controller that is used by the controller's onboard BIOS. This type of program is essential for hardware RAID since
you need to be able to set up and configure arrays before any operating system is loaded.
- Operating System Management Utility: This is a straight software
utility that runs after the operating system is loaded and running on the array. It allows
many of the same features as the setup program, except it is designed more towards
checking the status of the array and changing various parameters that control how it
operates. It typically also will allow operations that continue while an array is
operating normally, such as a rebuild on a fault-tolerant array. It works in conjunction
with the setup program.
I couldn't even begin to describe in detail all the features and options found in the
software utilities that come with high-end RAID controllers--they often come with manuals
that approach 200 pages in length. Of course, the software also varies significantly from
one manufacturer to another, and one product to another. Regardless of how it is set up,
the functionality of RAID management software allows you to perform the following basic
categories of functions:
- Controller Configuration: Configuring the controller and its features
at a hardware level. For example, setting how the internal cache, if any will work;
controlling alarms; selecting manual vs. automatic rebuild for failed drives, disabling
the BIOS if necessary, and so on.
- Array Configuration: Defining and configuring RAID arrays, setting up
which drives are in which arrays, and more.
- Physical Drive Management: Checking the status of drives connected to
the controller, formatting drives, designating drives as hot spares, and so on.
- Logical Drive Management: Creating logical drive volumes from an array,
formatting a logical volume, etc.
- SCSI Channel Management: For SCSI cards, controls various settings and
parameters related to setting up and managing the SCSI channels on the RAID controller.
Many of these are related to managing SCSI bus termination.
 Tip: As I mentioned
above, RAID controllers normally come with extensive documentation. You can usually find
the manuals for most RAID products in downloadable form on the web site of their
manufacturer. Reading through the software manual for a controller you are considering
buying can give you a much clearer picture of the controller's capabilities and
limitations than you will get from glossy marketing blurbs.
How about software RAID? Well, there's no surprises here: a management program is
required to manage all RAID features. There is obviously no BIOS setup program because
there is no controller BIOS, so everything is done at the operating system level. RAID
management functionality for Windows NT and 2000 is integrated into the Disk Administrator
tool that is used for managing disk volumes.
 Next: Remote Management
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