Compaq Infortrend manual 5 Mapping System Drives Mapping LUNs

Drive Channel:

Since all channels are strung between two controllers, each channel is connected to two chip processors, and each processor must occupy one channel ID. In redundant mode, both a Primary and a Secondary ID must be present on drive channels.

!The Primary-Secondary relationship between the controllers is automatically determined by firmware.

!You may have to create Primary and Secondary IDs separately on the host and drive channels if these IDs are not available. The configuration procedure will be discussed in section "10.3".

Mapping

!A logical unit made available through a Primary ID will be managed by the Primary controller, and that through a Secondary ID by the Secondary controller.

!Each channel ID (or an LUN under ID) will act as one virtual storage volume to the host computer.

Figure 10 - 5 Mapping System Drives (Mapping LUNs)

	! The diagram above displays a single host computer with two
	HBA cards allowing the connection of dual I/O paths. A host
	port ID is presented on each host port as the Primary ID or
	Secondary ID. Users may then map any logical configuration of
	drives to these LUN numbers. The result is that workload can be
Redundant Controller	10-7