•
If the free capacity in the FTSP becomes insufficient while FTRP balancing is being performed, an error oc-
curs and the balancing session ends abnormally. Note that insufficient physical capacity cannot be replaced
by other FTSPs.
•
When FTRP balancing is performed, an area for the work volume (the destination FTV which has the same
capacity as the source FTV) is secured in the FTRP to which the FTV belongs. As a result, the status of the
FTRP may temporarily become alarm status (the FTRP usage exceeds the "Caution" or "Warning" threshold).
This alarm state is removed once balancing completes successfully.
•
If the capacity of the FTRP is expanded during an FTRP balancing process, the balancing level might be less
than before.
•
FTRP balancing may not be performed regardless of what FTRP balancing level is used. FTRP balancing
availability depends on the physical allocation status of FTVs.
Optimization of Volume Configurations
The ETERNUS AF allows for the expansion of volumes and RAID group capacities, migration among RAID groups,
and changing of RAID levels according to changes in the operation load and performance requirements. There
are several expansion functions.
Table 24 Optimization of Volume Configurations
Function/usage Volume expansion
RAID group expan-
sion
Migration among
RAID groups
Changing the RAID
level
Striping for RAID
groups
RAID Migration
¡ (Adding capacity
during migration)
(*1)
´
¡ ¡
´
Logical Device Ex-
pansion
´
¡
´
¡ (Adding drives to
existing RAID
groups)
´
LUN Concatenation
¡ (Concatenating
free spaces)
´ ´ ´ ´
Wide Striping
´ ´ ´ ´
¡
¡: Possible, ´: Not possible
*1: For TPVs or FTVs, the capacity cannot be expanded during a migration.
● Expansion of Volume Capacity
•
RAID Migration (with increased migration destination capacity)
When volume capacity is insufficient, a volume can be moved to a RAID group that has enough free space.
This function is recommended for use when the desired free space is available in the destination.
•
LUN Concatenation
Adds areas of free space to an existing volume to expand its capacity. This uses free space from a RAID group
to efficiently expand the volume.
● Expansion of RAID Group Capacity
•
Logical Device Expansion
Adds new drives to an existing RAID group to expand the RAID group capacity. This is used to expand the ex-
isting RAID group capacity instead of adding a new RAID group to add the volumes.
1. Function
Optimization of Volume Configurations
57
FUJITSU Storage ETERNUS AF250 S2, ETERNUS AF250 All-Flash Arrays
Design Guide (Basic)
Copyright 2019 FUJITSU LIMITED
P3AG-1822-09ENZ0
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