Figure 32 Lun Concatenation; Figure 33 Lun Concatenation (Volume Concatenation) - Fujitsu ETERNUS DX S5 Series Design Manual

2. Basic Functions
Optimization of Volume Configurations
Figure 32 LUN Concatenation
RAID5 (3D+1P) 960GB × 4
RAID5 (3D+1P) 960GB × 4
LUN Concatenation is a function to expand a volume capacity by concatenating volumes.
Up to 16 volumes with a minimum capacity of 1GB can be concatenated.
Volumes can be concatenated up to 128TB (up to 1TB for ODX Buffer volumes).
Concatenation can be performed regardless of the RAID levels of the concatenation source volume and the
concatenation destination volume.
For SSDs and SEDs, the drives for the concatenation source and destination volumes must be the same type (SSD
or SED).
From a performance perspective, using RAID groups with the same RAID level and the same drives (type, size,
capacity, or rotational speed [for disks]) is recommended as the concatenation source.
The same key group setting is recommended for the RAID group to which the concatenation source volumes
belong and the RAID group to which the concatenation destination volumes belong if the RAID groups are
configured with SEDs.
A concatenated volume can be used as an OPC, EC, or QuickOPC copy source or copy destination. It can also be
used as a SnapOPC/SnapOPC+ copy source.
The LUN number stays the same before and after the concatenation. Because the server-side LUNs are not
changed, an OS reboot is not required. Data can be accessed from the host in the same way regardless of the
concatenation status (before, during, or after concatenation). However, the recognition methods of the volume
capacity expansion vary depending on the OS types.
Figure 33 LUN Concatenation (Volume Concatenation)
10GB
+
+
20GB
Unused area
Only Standard type volumes can be used for LUN Concatenation. The encryption status of a concatenated volume
is the same status as a volume that is to be concatenated.
LUN0 LUN0
LUN2 LUN2
Concatenation
LUN0 LUN0
LUN2 LUN2
Concatenation
30GB
RAID5 (3D+1P) 960GB × 4
LUN1 LUN1
Unused area
Concatenates
the unused area
and LUN2
RAID5 (3D+1P) 960GB × 4
LUN1
60GB
79 Design Guide