Performance Tuning; Assigned Cms; Figure 61 Assigned Cms; Table 52 Auto Assignment Of Assigned Cms (For 2 Cms) - Fujitsu ETERNUS DX S5 Series Design Manual

2. Basic Functions

Performance Tuning

Performance Tuning

Assigned CMs

A controller that controls access is assigned to each RAID group and manages the load balance in the ETERNUS
DX. The controller that controls a RAID group is called an assigned CM.
Figure 61 Assigned CMs
Switch
CM#0
Assigned
CM
RAID group #0
RAID group #2
ETERNUS DX
If specific controllers have a load bias, change the assigned CM to equalize the load.
If an assigned controller is disconnected for any reason, the assigned CM is replaced by another controller. After
the disconnected controller is installed again and returns to normal status, this controller becomes the assigned
CM again.
●
Auto Assignment of Assigned CMs
This section describes the selection criteria if auto assignment is selected for an assigned CM when RAID
groups are created. It is also possible to manually change the assigned CM.
The assigned CM is determined by the value when the RAID group number is divided by the number of
controllers. If a CM exists that is not installed or is malfunctioning, the assigned CM is allocated such that
the load is evenly distributed across the CMs that are running normally.
The following table shows the assigned CM when all CMs are installed and are running normally.
Table 52 Auto Assignment of Assigned CMs (for 2 CMs)
The value when the RAID group number is divided by the
number of controllers
Even number
Odd number
Table 53 Auto Assignment of Assigned CMs (for 4 CMs)
The remainder when the RAID group number is divided by the
number of controllers
0
The assigned CM of the RAID
Switch
group controls access
CM#1
Assigned
CM
RAID group #1
Assigned CMs (auto assignment)
CE#0 CM#0
CE#0 CM#1
Number of CMs (number of CEs)
2 (1CE)
CE#0 CM#0
121
4 (2CE)
CE#0 CM#0
Design Guide