Setting the Redundant Path Configuration
Does my Controller support this feature? See Supported features.
Redundant path is supported only on external PERC cards that use firmware version 6.1 and later. A redundant path internal to the system is not supported. MD1xxx enclosures are supported.
For redundant paths, the enclosure must be in the Unified mode however specific port connections are not required. A connection from either controller ports to either EMM In ports creates the redundant path if two cables are used. But, Redundant Path continues to appear in the field even as the redundant path is removed. The redundant path ceases to appear only when it is cleared in the storage management.
In a daisy-chain scenario, more than one enclosure can be connected to a controller in a redundant path mode. You can connect up to four MD1400 and MD1420 to a PERC H840 controller and SAS 12 Gbps adapter in a daisy-chain connection. For information about using the single and multiple multipath connections on 4-port controllers, see Set up Single and Multiple Multipath connections. For an example of a daisy-chain configuration, see the following image:

Storage Management does not permit connecting the first enclosure in a single path and attaching the subsequent enclosures in multipath. All enclosures must be connected in multipath to enable the multipath view.
If the communication channel between the connector and the first enclosure is lost, the redundant path configuration is lost. In this case, the health of the logical connector is displayed as critical. Go to the Information/Configuration page of the logical connector to view details of the Path Health. For a brief outline of this scenario, see the following table:
Health of Logical Connector | Path between Controller and Enclosure 1 | |
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Connector 0 (C0) | Connector 1 (C1) | |
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Available | Available |
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Available | Disconnected |
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Disconnected | Available |
However, 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.
Health of Logical Connector | Path between Enclosure n and Enclosure n +1 | |
---|---|---|
Connector 0 (C0) | Connector 1 (C1) | |
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Available | Available |
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Available | Degraded |
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Disconnected | Available |
In the above scenario, the enclosure status is displayed as Warning. Clicking Information/Configuration in the Enclosures page displays all enclosure components (EMMs, Fans, Physical Disks, Power Supplies, and Temperature) in normal condition. The Path Failure message indicates that the enclosure has lost a communication path to the controller and the enclosure is no longer in redundant path mode.
NOTE: If Storage Management displays a
Path Failure message for a Logical Connector after a reboot, use the
Clear Redundant Path View, provided in the
Change Controller Properties controller task, and restart the system. Use this command only if you have intentionally removed the multipath connection while rebooting the system.
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