System information

Advanced Functions
5-26
• Snapshot Roaming
The snapshot configurations are stored in the disks of the secondary volume. If “Auto Array Roaming Control” option
is enabled please see 2.7.16 Miscellaneous on page 2-37, foreign hard disks with snapshot configurations can be
automatically restored during the controller boo-up. However, if “Auto Array Roaming Control” option is turned off or
auto array roaming does not work due to configuration conflict, configurations of disk groups and logical disks have to be
restored first by importing the foreign hard disks, and then you may proceed to manually import the snapshots by GUI or
CLI please see 2.7.12 Array roaming on page 2-35.After the snapshots are imported either automatically or manually,
you need to set their LUN mappings.
5.5 Dynamic Capacity Management
The RAID controller enables flexibility in capacity configuration and reconfigurations for the following benefits:
• Improving the utilization of disk capacity
• Lowering the cost of hard disks in term of procurement and energy
• Easy management without down time
• Comprehensive capacity management utilities
The firmware utilities below allow you to increase disk space:
• Delete unused logical disks to release free space (Section 2.6.4 Logical disks)
• Delete unused volumes to release free logical disks (Section 2.6.5 Volumes)
• Expand a disk group by adding hard disks to it (Section 2.7.1 Expanding disk groups)
• Shrink under-utilized logical disks to release free space (Section 2.7.5 Shrinking logical disks)
• Shrink under-utilized volumes to release free logical disks (Section 2.7.7 Shrinking volumes)
The firmware utilities below allow you to manage or utilize free disk space:
• Create logical disks using free space on a disk group (Section 2.6.4 Logical disks)
• Create volumes using one or more free logical disks (Section 2.6.5 Volumes)
• Defragment a disk group to merge free chunks into one (Section 2.7.2 Defragmenting disk groups)
• Expand over-utilized logical disks with free chunks (Section 2.7.4 Expanding the capacity of logical disks in a disk
group)
• Expand over-utilized volumes with free logical disks (Section 2.7.6 Expanding volumes)
• LUN resizing (capacity expansion/shrink) procedures
The resizing of a logical disk or volume changes the usable capacity of a LUN. The LUN capacity change is made
effective after the background task is done for logical disk expansion, and it is effective immediately after your UI
operation for other resizing utilities (expanding volumes and shrinking volumes/logical disks).
To ensure your host can properly recognize and utilize the expanded space, please follow the steps below in order:
(1) Expand a logical disk or a volume by the firmware utility
(2) Wait till the background task is done (for logical disk expansion only)
(3) Rescan the physical drives by your operating system utility
(4) Expand the partition on the LUN by your partition editor
(5) Expand the file system on the expanded partition by your file system utility
To ensure your host can properly recognize and shrink the corresponding space without data loss, please follow the steps
below in order:
(1) Ensure enough unused space in the file system of a partition
(2) Shrink the file system on the partition by your file system utility
(3) Shrink the partition on the LUN by your partition editor
(4) Shrink the corresponding logical disk or volume by the firmware utility
(5) Rescan the physical drives by your operating system utility
Note
Abnormal shutdown of the RAID system could cause data loss of the snapshot volume if
the lookup table on the secondary volume is not updated.