Dual Active Controllers

RAID-500UW/U2W Dual-Active Controllers Guide
This article describes the advanced features of RAID500, which are archived
via firmware update. One is Dual active redundant controller function. Through
this function, the secondary RAID controller shares part of loading on primary
controller. It makes that RAID500 is suitable for applications on Dual hosts and
redundant hosts.
Dual Active Controllers
The controllers work simultaneously under dual-active mode and it can get
better performance than active-standby architecture. By default, the redundant
controller function is set as active-standby mode. Under this way, the primary
controller takes over all operations on RAID-500 while standby one is idle. It is
not efficient for high-end application. So, dual-active redundant controller
mode is suitable for most of application
In addition, the dual-active concept is based on logical drive. It means there
must be two available logical drives on RAID500 system for both controllers.
Same firmware version
Same model name like IFT-3102UG or IFT-3102U2G.
Same Cache capacity
1. After cabling necessary connections, please launch ¡ View and Edit SCSI
drives¡ item to check if all disks can be detected before configuring RAID
2. Power off secondary controller, and refer below paths to enable redundant
controller function. (Ref. Figure 1)
View and Edit Peripheral devices-> Set Peripheral Device Entry->Redundant
controller-> Enable redundant controller function as Primary
Note: Actually, you can select ¡ Autoconfiugre Mode¡ to cut down
configuration time. But, with this way, it just set both controllers as Activestandby mode not dual active mode.
3. Power off controller 1(Unplug power connector on rear of controller), and
then power on controller 2. Follow above step to set controller 2 as
Figure 1
4. Power on both controllers. And a flicking ¡P¡ or ¡S¡alphabet on upper-right
corner of LCD screen stands this controller is primary or secondary.
5. Disable onboard terminators on all SCSI channels. To do this, it makes sure
the RAID500 works normally when a controller failure. (Ref. Figure 2)
View and Edit SCSI channels->¡ select a SCSI channel¡ ->SCSI Terminator->Disable.
Figure 2
6. Set SCSI ID 6 to secondary controller on each drive channel. This SCSI ID
has higher priority than another ID numbers except ID 7. And it will respond
failure status of controller faster. (Ref. Figure 3)
7. Assign SCSI ID to secondary controller on Host channel with following
procedures. (Ref. Figure 4)
View and Edit SCSI channels->Select Host Channel->View and Edit SCSI ID->ID
0(Primary Controller)->Add SCSI channel ID->Secondary Controller
Note: You can set SCSI ID of primary and second controllers to any numbers between
0~15 except the one occupied by host adapter. The step6 and step 7 are most
important for configuring Dual-Active redundant controllers.
Figure 3
Figure 4
After finishing above steps, you can go to create logical drive. The following
paragraph will describe how to let both RAID controllers take over various
logical drive or partitions. And the secondary controller will share loading of
primary controller.
In this example, there are four hard disks are created as two RAID 1 logical
drives. The logical drive 1 and logical drive 2 are mapped to primary controller
ID0, LUN0 as well as secondary controller ID1, LUN0 separately. Please refer
to below steps.
8. Map logical drives to various controllers.
View and Edit Host luns->CHL1 ID0->Logical Drive->¡ select a LUN you want¡->¡ Select
a logical drive¡ ->¡ Select a partition¡
9. Assign logical drive 2 to secondary controller. (Ref. Figure 5)
View and edit logical drives->¡ Select logical drive 2¡ ->Logical drive Assignemnt->Yes
Note: The ¡P1¡ in LG column has been changed to ¡S1¡.
View and Edit Host luns->CHL1 ID0->Logical Drive->¡ select a LUN you want¡->¡ Select
a logical drive¡ ->¡ Select a partition¡
Figure 5
11. With Windows NT disk administrator, these logical drives are recognized
as physical hard disks. (Ref. Figure 6)
Figure 6