Set up Single and Multiple Multipath connections

On OpenManage 10.0.1 and later versions, controllers that have four ports enable you to connect enclosures in single multipath and multiple multipath connections. At a time, you can connect a maximum of four enclosures in multiple multipath connections. However, you can connect a maximum of eight enclosures in a singlepath. For external HBAs, if the communication between the connector and the first enclosure is lost, then the redundant path is not displayed on the UI but is indicated as a single-path connection to the enclosure.

The permitted multipath connection combinations for connecting enclosures are:

  • 0 and 1—Single Multipath
  • 2 and 3—Single Multipath
  • (0,1) and (2,3)—Multiple Multipath
NOTE: Tape drives and enclosures must not be connected to an HBA355e Adp simultaneously.

Here is an example of connecting MD1420 with a 4-port HBA355e Adp in the single multipath arrangement:

Figure 1. Connecting a 4-port controller to enclosures in Single Multipath

This connection diagram shows connecting a 4-port controller to enclosures in a single multipath connection.

To enhance load balancing and improve IOPS, you can create two multipaths by using the four ports of a 4-port HBA355e Adp. The permitted connector (port) combinations are (0,1) and (2,3). An example to multipath connection arrangement is given here:

Figure 2. Connecting a 4-port controller to enclosures in Multiple Multipath

This connecton diagram shows connecting a 4-port controller to enclosures in Multiple Multipath

Similarly, you can connect a maximum of two Array584EMM enclosures to a 4-port HBA355e Adp.

NOTE: MD14xx and Array584EMM enclosures cannot be connected to the same HBA355e Adp.

If the communication channel between any two enclosures is lost, the redundant path configuration is degraded, and the health of the logical connector is displayed as Degraded. For a brief outline of this scenario, see the following table:

Table 1. Path between Enclosure n and Enclosure n +1
Health of Logical Connector Path between Enclosure n and Enclosure n +1
Connector 0 (C0) Connector 1 (C1)
Available Available Available
Disconnected Available Degraded