System information

Advanced Functions
5-31
• Disk group expansion to consolidate free chunks
When disk group expansion is executed in a disk group where free chunks between logical disks exist, the free chunks
are consolidated and placed in the end space of the disk group after expansion.
5.5.5 Volume expansion and shrink
The capacity of a volume can be online expanded by adding the logical disks to the volume, which concatenates the
space of each logical disk to form a larger capacity. Because the expansion is done instantly without incurring any
background tasks, you can quickly start using the added capacity without waiting. Users can also reduce the capacity of
a volume by removing the concatenated logical disks. Freely expanding and shrinking a volume enables efficient storage
resource management.
Striping: A volume formed by single volume unit.
Concatenating: A volume formed by multiple volume units.
Note
It is suggested that defragmentation should be performed during disk group expansion. In the
cases shown in Figures 5-24, 5-25, and 5-26, defragmentation forms an organized collocation for
all logical disks and free chunks after expansion.
LD 1
LD 1
Free
chunk
LD 3
LD 3
Disk group (before) Disk group (after)
MD 0 MD 1 MD 2 MD 3 MD 4MD 0 MD 1 MD 2
Free
chunk
Free
chunk
Figure 5-26 Disk group expansion to consolidate free chunks
MV 1 MV 2
VOL 1
MV 3
MV 4
VU 1:1
Figure 5-27 Striping member volumes
VOL 2 (concatenating)
VU 2:1 VU 2:2 VU 2:3 VU 2:4
MV 2:1 MV 2:2 MV 2:3 MV 2:4
Figure 5-28 Concatenating member volumes