Creating pairs

When you create the initial copy, all data in the P-VOL on the primary system is copied to the S-VOL on the secondary system. The P-VOL remains available to the host for I/O operations.

Prerequisite information

• The initial copy is performed from the primary system.

• S-VOLs must be offline to all hosts.

• Ports must be configured for TrueCopy.

• The primary and secondary system must be configured for TrueCopy. See Adding remote connection for more information.

• Stop Performance Monitor before the initial copy to avoid overloading with TCP/IP traffic.

• During this operation, you select P-VOLs and S-VOLs by Port ID, Host Group ID or iSCSI target ID and LUN.

• During this operation, you can specify multiple P-VOLs to be paired, but only one S-VOL. To plan how the system assigns subsequent S-VOLs, see the bullet, "When creating multiple pairs concurrently...." in the section on planning pairs and pair volumes in the Hitachi TrueCopy® User Guide

• During this operation, you can specify whether to fence the P-VOL when an error occurs. This is discussed in detail in the planning section on fence level options in the Hitachi TrueCopy® User Guide.

• During this operation, you can specify the priority for initial copy operations. When performing more initial copies than specified for Maximum Initial Copy Activities (during configuration), see the discussion in the planning section on priority settings for initial copy operations in the Hitachi TrueCopy® User Guide.

To create initial copies

1. In Hitachi Command Suite:

1. On the Resources tab, expand the Storage Systems tree, right-click the target storage system and click Remote Replication.

In Device Manager - Storage Navigator

1. Click Storage Systems, and then expand the Storage Systems tree.

2. In the Storage Systems tree, click Replication > Remote Replication.

2. In the Remote Replication window, click the TC Pairs tab then click Create TC Pairs.

3. For Remote Storage System, select the following:

• The secondary system's Model/Serial Number and Path Group ID.

• For Path Group ID, select the path group ID.

4. In the Primary Volume Selection box, for LU Selection, select the Port ID and Host Group Name or iSCSI Target Alias. Selecting Any places all LUNs within the specified port in the Available LDEVs table. No further action is required at this time.

 Available LDEVs limitations:

• When using a virtual storage machine with Hitachi Virtual Storage Platform G200, G400, G600, Available LDEVs displays physical LDEV information, not virtual.

• nondisruptive migration volumes do not display in Available LDEVs.

5. In the Secondary Volume Selection box, specify the following:

1. For Base Secondary Volume, select the initial S-VOL's Port ID, Host Group ID / iSCSI Target ID, and LUN ID. If you are selecting only one P-VOL, this LU is the secondary volume. If you select multiple P-VOLs for pairing, this LUN is the base S-VOL that is assigned to the first P-VOL and from which subsequent S-VOL LUNs are assigned to the list of P-VOLs.

 In USP V/VM and VSP, LUN IDs display in hexadecimal numbers. In Hitachi Virtual Storage Platform G200, G400, G600, LUN IDs display in decimal or hexadecimal numbers. If you have selected the decimal notation, when assigning an S-VOL in a USP V/VM or VSP storage system, make sure to convert the hexadecimal LUN ID number to decimal.

2. For Selection Type, select the method for assigning S-VOLs when multiple primary volumes are selected.

- With Interval, specify an interval the system skips between secondary system LU numbers.

3. - With Relative Primary Volume, the system assigns secondary system LU numbers based on proximity to P-VOL LU numbers.

6. Click Options to define the following optional settings:

1. For Primary Volume Fence Level, specify whether the primary system allows or rejects write operations to the P-VOL when the pair is split due to an error.

- Data: The P-VOL cannot be written to.

- Status: The P-VOL can be written to if the primary system can change S-VOL status to PSUE; otherwise it cannot be written to.

- Never: The P-VOL can always be written to.

2. For Initial Copy Type, specify whether to copy data from P-VOL to S-VOL during the operation.

- Entire Volume creates the pair and copies data to the S-VOL. (Default)

- None creates the pair but data is not copied to the S-VOL. This requires that data in the P-VOL and S-VOL are already identical.

3. For Copy Pace, specify the number of tracks to be copied per remote I/O during the operation. The range is 1-15; 15 is the default. This option affects performance as follows:

- 1 to 5 is slow, improves performance and lowers impact to host I/O.

- 5 to 10 is medium.

- 11 to 15 is fast, may lower performance and increase impact to host I/O.

4. For Initial Copy Priority, specify the scheduling order for the initial copy operation. The range is 1 to 256; 32 is the default.

If a time-out error occurs during this operation, the order specified in Initial Copy Priority may not run as expected. A time-out error can occur because of the CU configuration or data path error. Review the error, delete the pair with an error, then retry the operation.

7. Back again in the Primary Volume Selection box, select the primary volume to be copied first and click Add. The volume and pair information moves to the Selected Pairs table.

In the Selected Pairs table, you can change pair options by selecting it and clicking Change Settings. Remove a pair by selecting it and clicking Remove.

8. Click Finish.

9. In the Confirm window, review the settings and enter a task name in the Task Name box.

10. Click Apply to save your settings in the system.

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