System information
Introduction
1-9
Data integrity assurance
For better system reliability, you are advised to set policies for handling exceptions, like to start disk cloning when SMART
warning is detected or too many bad sectors of a hard disk are discovered (see 2.8.1 Hard disks on page 2-38), or to
turn off write cache when something wrong happens (see 2.9.5 Miscellaneous on page 2-47). You may also schedule
periodic maintenance tasks to do disk scrubbing(see 2.7.9 Scrubbing on page 2-33) for defected sectors recovery or to
do disk self-tests (see 2.7.11 Performing disk self test on page 2-34).
Miscellaneous settings
There are also minor settings that you might need to do, like checking UPS (see 2.9.4 UPS on page 2-47), time setup
(see 2.10.4 System Time on page 2-51), changing password (strongly suggested) and etc.
Saving the configurations
If you’ve done all the configurations, please save the configurations to files (human-readable text file for your own
reference and binary file for restoring the configurations if any disaster happens).
1.7 Maintaining the RAID System
Properly configuring RAID systems is a good starting point, but you need to do regular checking and reconfiguration to
make sure your RAID systems are healthy and delivering the best throughout the lifetime.
• Constantly monitoring RAID system health
You can quickly get an overview of the RAID system health by accessing the monitoring page of the Web GUI (see 2.2
Monitor Mode on page 2-4). You probably need to do so only when receiving event notification email or traps. All the
events are described in the Appendix D, each of which has suggested actions for your reference. You need to watch the
status of chassis components, like fans, power supply units, battery module, and controller module. You need also check
the status of hard disks, and the I/O statistics (see 2.11 Performance Management on page 2-53) to know the system
loading level and distribution. A hard disk with long response time or lots of media errors reported could be in trouble.
• Performing online maintenance utilities
Comprehensive maintenance utilities are offered for ensuring the best condition and utilization of your RAID systems all
through its lifetime. They include data integrity assurance, capacity resource reallocation, and RAID attributes migration.
Data integrity assurance
For data long-term integrity assurance and recovery, you may use disk scrubbing (see 2.7.9 Scrubbing on page 2-33),
disk cloning (see 2.7.8 Cloning hard disks on page 2-32), DST (see 2.7.11 Performing disk self test on page 2-34),
and SMART (see s 2.8.1 Hard disks on page 2-38). For how these can help you, please go to Appendix B: Features
and Benefits.
Capacity resource reallocation
If you’d like to add more disks for capacity expansion, you can use disk group expansion (see 2.7.1 Expanding disk
groups on page 2-29). Resizing logical disks and volumes ( 2.7.4 Expanding the capacity of logical disks in a disk
group on page 2-31 to 2.7.6 Expanding volumes on page 2-32) can also help you to transfer the unused capacity of a
LUN to others that are desperate for more space without any impact to other LUNs. If unused space is scattered, you can
use disk group defragmentation (see 2.7.2 Defragmenting disk groups on page 2-30) to put them together.
RAID level and strip size migration
Changing RAID level of a logical disk (see 2.7.3 Changing RAID level / stripe size for logical disks on page 2-30) will
significantly affect the performance, reliability, and space utilization. For example, you may add one disk to a two-disk
RAID 1 disk group and change its RAID level to RAID 5, such that you can have a three-disk RAID 5 disk group, offering
usable space of two disks. On the other hand, changing stripe size affects only the performance, and you may do as
many online experiments as possible to get the performance you want.
Schedule a task
You won’t want the performance degradation during the execution of the online maintenance utilities, which very like
need non-trivial amount of time. To avoid such impact, you’re allowed to schedule a task execution to any time you want
(see 2.7.14 Schedule task on page 2-36), like during off-duty hours. You can get event notifications when the task is
done (or unfortunately fails), or at a user-configurable percentage of the task progress (see 2.7.16 Miscellaneous on
page 2-37).