Managing SRDF/A Starting a session

 

 

Topic

Managing SRDF

Selections

Select SRDF management tool: Managing SRDF using Symmetrix Management Console (SMC)

Select a task: Managing SRDF/A

Select task(s): Starting a session

 

 

Contents

·             Setting the SRDF/A mode. 3

·             Creating dynamic SRDF device pairs. 4

·             Creating a dynamic SRDF group.. 6

·             Performing SRDF control operations. 8

 


 

 

·        Setting the SRDF/A mode

 

Overview

This procedure explains how to set the SRDF/A mode for SRDF/A operations.

Prerequisite: This dialog is only available for SRDF groups using Enginuity 5671 or later.

This procedure is from the SMC online help.

 

1.   

Open the dialog

 

Right-click the SRDF device group (or composite group) containing the R1 or R2 devices and select Replication, SRDF Settings to open the Set SRDF Mode dialog box.

 

 

2.   

Enter information

Select Asynchronous from the Set Mode pull-down list.

(Descriptions of all SRDF Modes are contained at the end of this procedure.)

 

 

3.   

Select device pairs

If you are not setting the mode for all devices in the Device Pair List, use the Ctrl and Shift keys to select the device pairs.

 

4.   

Optional: Consistent option

Select the Consistent option to keep the R2 SRDF/A capable devices in a consistent state (for device pairs operating in asynchronous mode).

 

5.   

Click OK.

Click OK to set the SRDF group mode to Asynchronous.

 


 

6.   

List of Modes

·          Synchronous - provides the host access to the source (R1) device on a write operation only after the array containing the target (R2) device acknowledges that it has received and checked the data.

·          Asynchronous - the Symmetrix array acknowledges all writes to the source (R1) devices as if they were local devices. Host writes accumulate on the source (R1) side until the cycle time is reached and are then transferred to the target (R2) device in one delta set. Write operations to the target device can be confirmed when the current SRDF/A cycle commits the data to disk by successfully de-staging it to the R2 storage devices.

·          Semi Synchronous - the Symmetrix array containing the source (R1) device informs the host of successful completion of the write operation when it receives the data. The RDF (RA) director transfers each write to the target (R2) device as the RDF links become available. The Symmetrix array containing the target (R2) device checks and acknowledges receipt of each write.

·          AC WP Mode On - (adaptive copy write pending) the array acknowledges all writes to the source (R1) device as if it was a local device. The new data accumulates in cache until it is successfully written to the source (R1) device and the remote director has transferred the write to the target (R2) device.

·          AC Disk Mode On - for situations requiring the transfer of large amounts of data without loss of performance; use this mode to temporarily to transfer the bulk of your data to target (R2) devices; then switch to synchronous or semi synchronous mode.

·          Domino Mode On - ensures that the data on the source (R1) and target (R2) devices are always in sync. The Symmetrix array forces the source (R1) device to a Not Ready state to the host whenever it detects one side in a remotely mirrored pair is unavailable.

·          Domino Mode Off -  the remotely mirrored device continues processing I/Os with its host, even when an SRDF device or link failure occurs.

·          AC Mode Off - turns off the AC disk mode.

·          AC Change Skew - modifies the adaptive copy skew threshold. When the skew threshold is exceeded, the remotely mirrored pair operates in the predetermined SRDF state (synchronous or semi-synchronous). As soon as the number of invalid tracks drop below this value, the remotely mirrored pair reverts back to the adaptive copy mode.

·          (R2 NR If Invalid) On - sets the R2 device to Not Ready if there are invalid tracks.

·          (R2 NR If Invalid) Off  - turns off the (R2 NR_If_Invalid) On mode.

 

7Table of Contents

 

·        Creating dynamic SRDF device pairs

 

Overview

This procedure explains how to create SRDF device pairs.

This procedure is from the SMC online help.

 

7.   

Open the dialog

 

Right-click the Symmetrix ID and select Replication, SRDF Configuration, Create SRDF Pair to open the Create SRDF Pair dialog box.

 

 

 

8.   

Enter information

Select the RDF Type, RDF Group, and optionally enter a name for a new device group.

 

9.   

Optional: Filter the Source device list

 

Use the Filters to populate the Source device list with specific configurations, device emulation types, and/or device capacity sizes.

 

10.  

Select pairs

When you click on a Source device, the Target devices that can be paired with that device display in the Target table. Select both the Source and Target devices and click Add to move them to the Device Pair List.

 

 


 

11.  

Select Synchronization type

 

Select one of the pair synchronization boxes:

 

·          Invalidate R1 — creates the dynamic SRDF paired devices and invalidates the source devices. (Device must be Write Disabled)

·          Invalidate R2 — creates the dynamic SRDF paired devices and invalidates the target devices. (Device must be Write Disabled)

·          Establish — begins copying data to the target device(s), synchronizing the dynamic RDF device pairs (after the RDF device pairs are created).

·          Restore — begins copying data to the source device(s), synchronizing the dynamic RDF device pairs.

Select one of the pair synchronization boxes

 

12.  

Click OK

Click OK to apply the create pair operation and exit the dialog.

13.  

Click OK

Click OK to verify invoking the create pair control operation.

14.  

Click OK

Click OK to acknowledge that the control operation has returned successfully.

 

7Table of Contents

 

·        Creating a dynamic SRDF group

 

Overview

This procedure explains how to create an SRDF group.

This procedure is from the SMC online help.

 

15.  

Open the dialog

 

Right-click the Symmetrix ID and select Replication, SRDF Configuration, Create SRDF Group to open the Create SRDF Group dialog box.

 

 

 

16.  

Enter information

Select a Communication Protocol (Fibre Channel, FarPoint, or Gigabit Ethernet). The value you select will populate the Director list.

 

17.  

 

Enter an RDF Group Label (maximum 10 characters).

 

18.  

 

Enter an RDF Group Number. This number must be unique per Symmetrix array.

 

19.  

 

Select one or more local Director(s) through which this RDF group will communicate.

 

20.  

Optional

Optional: Select a Link Limbo Period. This is a length of time for the array to continue checking the local RDF link status. (The range is 0-120 seconds, default is 10.)  If the link status is Not Ready after the link limbo time, the devices are made Not Ready to the link.

 

21.  

Optional

Optional: Select Link Domino (sets the domino mode for the source (R1) device, which ensures that the data on the source (R1) and target (R2) devices are always in sync) and/or Auto Link Recovery (specifies whether to enable the group for auto link recovery).

 

 

22.  

 

Select the Remote Symmetrix ID.

 

23.  

 

Enter a remote RDF Group Number. This number must be unique per Symmetrix array.

 

24.  

 

Select one or more Remote Director(s) through which this RDF group will communicate.

 

 

25.  

Optional

Optional: Select a Remote Link Limbo Period (specifies a length of time to continue checking the remote RDF link status).

 

 

26.  

Optional

Optional: Select Remote Link Domino (sets the domino mode for the target (R2) device, which ensures that the data on the source (R1) and target (R2) devices are always in sync) and/or Remote Auto Link Recovery (specifies whether to enable the remote group for auto link recovery).

 

 

27.  

Click OK

Click OK to create the group and exit the dialog.

 

28.  

Click OK

Click OK to acknowledge the confirmation message that the RDF Group has been created.

 

 

7Table of Contents

 

·        Performing SRDF control operations

 

Overview

This procedure explains how to perform an SRDF control operation using devices in a device group.

This procedure is from the SMC online help.

 

29.  

Open the dialog

 

Right-click the device group and select Replication, SRDF Control to open the SRDF wizard.

 

 

30.  

 

Select the RDF Type and the Action (in this example, The RDF Type is STD R1 and the Action is Split). By default, the system displays the next logical action in the Action drop-down list.

 

31.  

Select device pairs

Use the Ctrl and Shift keys to select the device pairs, or click Select All to select all the SRDF device pairs.

 

 

32.  

Click Next

Click Next to complete the operation request.

 


 

33.  

 

Optional: Select any of the operation Options:

·         Immediate: Causes the suspend, split, and failover actions on asynchronous devices to happen immediately.

·          Bypass: Bypasses the Symmetrix exclusive locks for the local and/or remote array during SRDF operations.

·         Force: Overrides any restrictions and forces the operation, even though one or more of the paired devices may not be in the expected state. Use caution when checking this option because improper use may result in data loss.

·          SymForce: Forces an operation on the device pair including pairs that would be rejected. Use caution when checking this option because improper use may result in data loss.

 

34.  

Click Finish.

35.  

Click OK

Click OK to confirm the SRDF control operation.

36.  

Click OK

Click OK to acknowledge the successful return from the control operation.

37.  

View the session status

To view the status of the SRDF session, select the device group (in Properties view) and click the RDF Query tab.

 

The key things to verify are the Pair State.

 

7Table of Contents