Title

PlannedSwitchfromAsyncTargettoPrimaryWorkloadSiteUsingSRDF/Star_sym001 Planned Switch from Asynchronous Target to Primary Workload Site Using SRDF/Star

Overview

This procedure provides the steps required to gracefully return Star control to the primary workload site (SiteA) from the asynchronous target site (SiteC) and resume star protection.This procedure is based on content from the following EMC technical documentation: EMC Solutions Enabler Symmetrix SRDF Family CLI White Paper: Implementing EMC SRDF/Star Composite Groups on Open Systems Applied Technology EMC Solutions Enabler Using SYMCLI to Implement SRDF/Star Technical NotesThese documents can be obtained from the EMC Powerlink website at:

http://Powerlink.EMC.comNote: For this procedure, the primary workload site is named SiteA, the synchronous target site is SiteB, and the asynchronous target site is SiteC, as shown in the following illustration:

1. A planned switch will include a halt action to ensure that data is equal at all three sites. Log in to the control server for the asynchronous target site (SiteC) and ensure the primary workload site (SiteA) and the synchronous target site (SiteB) are in the Connected or Protected states. This procedure requires both sites to be connected and optionally allows one of the sites to be protected. Verify that the states are Connected or Protected for both target sites by executing a command similar to the following:

symstar -cg train125 queryWhen this command is executed, you should see a message similar to the following:

Site Name : SiteC

Workload Site : SiteC

1st Target Site : SiteA

2nd Target Site : SiteB

Composite Group Name : train125

Composite Group Type : RDF1

Workload Data Image Consistent : Yes

System State:

{

1st_Target_Site : Connected 2nd_Target_Site : Protected STAR : Unprotected

Mode of Operation : Concurrent

If the sites are not in these states, issue commands similar to the following to obtain at least the connected/connected state so the halt command will succeed. symstar -cg train125 connect -site SiteA

symstar -cg train125 connect -site SiteB(

2. Shut down ALL host applications at the current workload site (asynchronous target site - SiteC) using devices within the Star composite group that is being switched. Once all applications have been shut down, halt the Star system by executing a command similar to the following:symstar -cg train125 halt

! Caution: The halt operation write disables all devices in the composite group at all sites. Ensure no applications are using the devices at any site before executing this command. !When this command is executed, you should see a message similar to the following:

A STAR Halt operation is in progress for composite group train125. Please wait...

Halt ......................................................... Started. . .

Halt ......................................................... Done

Verify that the halt operation was successful by executing a command similar to the following:

symstar -cg train125 queryWhen this command is executed, you should see a message similar to the following:Site Name : SiteC

Workload Site : SiteC

1st Target Site : SiteA

2nd Target Site : SiteB

Composite Group Name : train125

Composite Group Type : RDF1

Workload Data Image Consistent : Yes

System State:

{

1st_Target_Site : Halted

2nd_Target_Site : Halted

STAR : Unprotected

Mode of Operation : Concurrent

}

Last Action Performed : Halt

Last Action Status : Successful

Last Action Timestamp : 06/02/2010_13:12:19. . .(

3. Log in to a control server at the primary workload site (SiteA) and switch the Star workload back to that site; then protect the data at all sites using SRDF/Star by executing a set of commands similar to the following:

Note: The devices are available for applications to use immediately following the switch to the primary workload site (SiteA).

symstar -cg train125 switch -site SiteA

symstar -cg train125 connect -site SiteB

symstar -cg train125 connect -site SiteC

symstar -cg train125 protect -site SiteB

symstar -cg train125 protect -site SiteC

symstar -cg train125 enable

Once these commands have been executed, verify that SRDF/Star protection is enabled by executing a command similar to the following: symstar -cg train125 query

When this command is executed, you should see output similar to the following:

Site Name : SiteA

Workload Site : SiteA

1st Target Site : SiteB

2nd Target Site : SiteC

Composite Group Name : train125

Composite Group Type : RDF1

Workload Data Image Consistent : Yes

System State:

{

1st_Target_Site : Protected

2nd_Target_Site : Protected

STAR : Protected

Mode of Operation : Concurrent

}

Last Action Performed : Enable

Last Action Status : Successful

Last Action Timestamp : 05/25/2010_09:51:47

. . .

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PlannedSwitchfromAsyncTargettoPrimaryWorkloadSiteUsingSRDF/Star_sym001