Choosing the correct recovery procedure

After a failure in a MetroCluster configuration, you must select the correct recovery procedure, depending on the extent of the failure.

Evaluate the disaster, using the following table and examples to select the appropriate recovery procedure.

Scope of failures at disaster site	Procedure
No controller module failure Other hardware has failed	Recovering from a non-controller failure
Single controller module failure or failure of FRU components within the controller module Drives have not failed	If a failure is limited to a single controller module, you must use the controller module FRU replacement procedure for the platform model. In a four or eight-node MetroCluster configuration, such a failure is isolated to the local HA pair. AFA and Hybrid Documentation Center
Single controller module failure or failure of FRU components within the controller module Drives have failed	Recovering from a multi-controller or storage failure
Single controller module failure or failure of FRU components within the controller module Drives have not failed Additional hardware outside the controller module has failed	Recovering from a multi-controller or storage failure You should skip all steps for drive assignment.
Multiple controller module failure (with or without additional failures) within a DR group	Recovering from a multi-controller or storage failure

Controller module failure scenarios in eight-node MetroCluster configurations

Single controller module failures in a single DR group

In this case the failure is limited to an HA pair.

If no storage requires replacement, you can use the controller module FRU replacement procedure for the platform model.
AFA and Hybrid Documentation Center
If storage requires replacement, you can use the multi-controller module recovery procedure.
Recovering from a multi-controller or storage failure

This scenario applies to four-node MetroCluster configurations also.

Two controller module failures in a single DR group

In this case the failure requires a switchover. You can use the multi-controller module failure recovery procedure.

This scenario applies to four-node MetroCluster configurations also.

Single controller module failures in separate DR groups.

In this case the failure is limited to separate HA pairs.

If no storage requires replacement, you can use the controller module FRU replacement procedure for the platform model.
The FRU replacement procedure is performed twice, once for each failed controller module.
AFA and Hybrid Documentation Center
If storage requires replacement, you can use the multi-controller module recovery procedure.
Recovering from a multi-controller or storage failure

Three controller module failures spread across the DR groups

In this case the failure requires a switchover. You can use the multi-controller module failure recovery procedure for DR Group One.

You can use the platform-specific controller module FRU replacement procedure for DR Group Two.

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