Validations Made by the Data Replication Subsystem

When the SRDF device group is added to a protection group, the data replication layer makes the following validations.

• The specified device group name exists in the SRDF configuration.

• The replication role matches the SRDF protection group role.

• The EMC Symmetrix source, R1SID, and the EMC Symmetrix target, R2SID, can be reached.

When an SRDF device group is added to a protection group, a Geographic Edition data replication resource is automatically created by this command. This resource monitors data replication state. The name of the resource is sc_geo_dr-SRDF-protection-group-device-group, where protection-group is the name of the protection group and device-group is the name of the device group. This resource is placed in the corresponding Geographic Edition resource group, which is named sc_geo_dr-SRDF-protection-group.

This section provides the following information:

• How the State of the SRDF Device Group Is Validated

• Determining the State of an Individual SRDF Device Group

• Determining the Aggregate SRDF Device Group State

• Determining the SRDF Pair State

How the State of the SRDF Device Group Is Validated

The state of each SRDF device group is mapped to the Geographic Edition resource group state. The symrdf -g device-group query command returns this state.

The remainder of this section describes the individual device group states and how these states are validated against the local role of the protection group.

Determining the State of an Individual SRDF Device Group

An individual SRDF device group can be in one of the following states:

• Synchronized

• SynInProg

• Failedover

• R1 Updated

• R1 UpdInProg

• Split

• Suspended

• Partitioned

• Invalid

Determining the Aggregate SRDF Device Group State

If a protection group contains only one SRDF device group, then the aggregate device group state is the same as the individual device group state.

When a protection group contains multiple SRDF device groups, the aggregate device group state is obtained as described in the following table.

Table 2-1  Conditions That Determine the Aggregate Device Group State

Condition Aggregate Device Group State Any of the individual device group states are Invalid. Invalid Any of the individual device groups states are Partitioned and none of the individual device group states is Invalid. Partitioned One or more of the individual device groups states are Suspended and none of the individual device group states is Invalid, or Partitioned. Suspended One or more of the individual device groups states are Split and none of the individual device group states is Invalid, Partitioned, or Suspended. Split One or more of the individual device groups states are R1 UpdInProg and none of the individual device group states is Invalid, Partitioned, Suspended, or Split. R1 UpdInProg One or more of the individual device groups states are R1 Updated and none of the individual device group states is Invalid, Partitioned, Suspended, Split, or R1 UpdInProg. R1 Updated One or more of the individual device groups states are Failedover and none of the individual device group states is Invalid, Partitioned, Suspended, Split, R1 UpdInProg, or R1 Updated. Failedover One or more of the individual device groups states are SynInProg and none of the individual device group states is Invalid, Partitioned, Suspended, Split, R1 UpdInProg, R1 Updated, or Failedover. SynInProg All of the individual device group states are Synchronized. Synchronized

Determining the SRDF Pair State

The resource status message reflects the role and state of the RDF pair. For example, the resource status and status message of Faulted Split, is reported when the RDF pair is in a Split state.

The RDF pair state is mapped to the associated resource status as described in the following table.

Table 2-2  Mapping From the RDF Pair State to the Resource Status

Condition Resource Status Status Message The RDF pair state is Invalid and the pair state is not Incorrect Role. Faulted Invalid state The RDF pair state is Partitioned and the pair state is not Incorrect Role, or Invalid. Faulted Partitioned The RDF pair state is Suspended and the pair state is not Incorrect Role, Invalid, or Partitioned. Faulted Suspended The RDF pair state is SyncInProg and the pair state is not Incorrect Role, Invalid, Partitioned, or Suspended. Degraded SyncInProg The RDF pair state is R1 UpdInProg and the pair state is not Incorrect Role, Invalid, Partitioned, Suspended, or SyncInProg. Faulted R1 UpdInProg The RDF pair state is Split and the pair state is not Incorrect Role, Invalid, Partitioned, Suspended,SyncInProg, or R1 UpdInProg. Faulted Split The RDF pair state is Failed over and the pair state is not Incorrect Role, Invalid, Partitioned, Suspended,SyncInProg, R1 UpdInProg, or Split. Faulted Failed over The RDF pair state is R1 Updated and the pair state is not Incorrect Role, Invalid, Partitioned, Suspended,SyncInProg, R1 UpdInProg, Split, or Failed over. Faulted Replicating with role change The RDF pair state is Synchronized. Online Replicating

The state of the RDF pair determines the availability of consistent data in the partnership. When the state of the RDF resource on the primary or secondary cluster is Degraded or Faulted, the data volumes might not be synchronized even if the application can still write data from the primary volume to the secondary volume. The RDF pair will be in a Partitioned state and the invalid entries will be logged as the data is written to the primary volume. Manual recovery operations are required to resolve the error and resynchronize the data.