Accusys ExaRAID GUI - Manual (Page 37)

Introduction
1-12
largely depend on the information you collect. It is advised to write down
the information of users’ needs and environments as well as the
configurations in your mind, which can be very helpful guidance through
the all the lifetime of the RAID systems.
• Configuring the hardware settings and doing health check
After installing your RAID systems with necessary components, like hard
disks and transceivers, to your environment, enabling the user interfaces is
a prerequisite if you want to do anything useful to your RAID systems. The
only user interface that you can use without any tools is the LCD console,
by which the settings of the RS232 port and the management network
interface can be done to allow you to use the GUI and CLI (see 3.3 Menu
on page 3-6).
Now, do a quick health check by examining the GUI monitoring page to
locate any mal-functioning components in the chassis or suspicious
events (section 2.2). Follow the hardware manual to do troubleshooting, if
needed, and contact your supplier if the problems still exist. Make sure
the links of the host interfaces are up and all installed hard disks are
detected. Since your hard disks will be the final data repository, largely
influencing the overall performance and reliability, it is advised to use the
embedded self-test utility and SMART functions to check the hard disks
(see 2.8 Hardware Configurations on page 2-57 ). A better approach
would be to use benchmark or stress testing tools.
You need also be sure that all the attached JBOD systems are detected
and no abnormal event reported for the expansion port hardware (see
2.3 SAS JBOD Enclosure Display (for SAS expansion controller only) on
page 2-13). Sometimes, you will need to adjust the hardware parameters,
under your supplier’s advices, to avoid potential interoperability issues.
• Organizing and presenting the storage resources
The most essential configuration tasks of a RAID system are to organize
the hard disks using a variety of RAID settings and volume management
functions, and eventually to present them to host systems as LUNs (LUN
mapping). This is a process consisted of both top-down and bottom-up
methodology. You see from high-level and logical perspectives of each
host system to define the LUNs and their requirements. On the other hand,
you will do configuration starting from the low-level and physical objects,
like grouping the disk drives into disk groups.
Tradeoff analysis is required when choosing RAID levels, like using RAID 0
for good performance but losing reliability, or using RAID 6 for high
reliability but incurring performance penalty and capacity overhead. The
appendix provides information about the algorithms of each RAID level
and the corresponding applications. You can also use the embedded
volume management functions to build LUNs of higher performance and
larger capacity. The RAID system offers much flexibility in configurations,
like independently-configurable RAID attributes for each logical disk,