Compaq Infortrend Manuale Utente

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Infortrend
10-16
10.2.2 Limitations
 
Both controllers must be exactly the same.  Namely, they must operate
with the same firmware version, the same size of memory, the same
number of host and drive channels, etc.  If battery backup is preferred,
both should be installed with a battery module.
 
The takeover process should take less than one second (using SCSI or
Fibre for controller communications) to complete.
 
In redundant mode, each controller takes an ID on each channel bus.
This leaves the maximum number for disk drives on a SCSI bus to be 14.
 
Connection through Fibre hubs or switches is necessary for joining host
(Fibre) interfaces between controllers.  The EonRAID 2510FR is an
exception.  Its type-1 ports come with an onboard hub.
 
The controller defaults for ID settings are listed below:
Host
interface
Host channel
(Primary/Secondary)
Drive channel
(Primary/Secondary)
SCSI
0 / 1…
7 / 6
Fibre
112 / 113…
119 / 120
 
SCSI IDs 8 (PID) and 9 (SID) are the recommended defaults to the drive
channels of the SCSI-based dual-controller chassis using an integrated
backplane.
10.2.3 Configurable Parameters 
Primary or Secondary
If necessary, users can specify a particular controller as Primary or
Secondary.  By setting each controller to the "Autocfg" mode, the controllers
will decide between themselves which is the Primary and which is the
Secondary.
The controller firmware recognizes the two controllers used in a redundant
configuration as Primary or Secondary.  Two controllers behave as one
Primary controller.
Once the redundant configuration takes effect, user's configurations and
settings can only be done on the Primary controller.  The Secondary
controller then synchronizes with the configuration of the Primary controller,
making the configurations of two controllers exactly the same.