Creating a UR pair

When you create a pair, the pair relationship between the volumes is established, and the initial copy operation is performed. The P-VOL remains available to the host for I/O operations during the initial copy operation.

Before you begin

  • You can create a pair only from the primary storage system.
  • The S-VOL must be offline to all hosts.
  • The primary and secondary storage systems must already be configured, and the remote paths must already be defined.
  • The P-VOL capacity and S-VOL capacity must be the same (same number of blocks). To view the capacity in blocks, click Options Capacity Unit block in the Logical Devices window. If the capacity is displayed in GB or TB, a slight difference in P-VOL and S-VOL capacity might not be displayed.
  • Journal volumes must be registered to the journals that are associated with pairs.
  • Review the information on S-VOL volume numbers in the bullet on creating multiple pairs in the Universal Replicator User Guide topic on planning pair volumes.
  • If you are creating a UR delta resync pair, see the Universal Replicator User Guide
  • Make sure that Performance Monitor is stopped.

The following additional information may be useful to you before beginning the procedure:

  • You will select the volumes to be paired by port, host group ID or iSCSI target ID, and LUN ID. Make sure to have this information available.
  • You will assign master and restore journals to the P-VOL and S-VOL during the operation.
  • You will assign a mirror ID to the pair. This identifies the pair within the journal. A mirror refers to the pair within the journal.
  • If the mirror ID you will assign to the new pair contains an existing pair or pairs, the new pair’s volumes must belong to the same primary and secondary storage systems defined in the mirror.
  • In a 3DC multi-target configuration in which three UR sites are combined, you cannot create a UR pair with the second mirror if the first UR P-VOL is in the COPY status.
  • In a 3DC cascade configuration in which three UR sites are combined, you cannot create a UR pair between the intermediate and secondary sites if the UR S-VOL between the primary and intermediate sites is in the COPY status.

Procedure

  1. In the Explorer pane, expand the Storage Systems tree.

  2. Expand the target storage system tree, expand Replication, and click Remote Replication.

  3. In the UR Pairs tab, click Create UR Pairs.

  4. In the Create UR Pairs window, for Copy Type, select Universal Replicator.

  5. For Remote Storage System, select the secondary storage system’s Model/Serial Number and Path Group ID.

    • If the mirror contains an existing pair, the same Model/Serial Number as the existing pair’s must be selected.
    • If the secondary storage system is USP V/VM, only 0 can be selected for Path Group ID.

  6. In the Primary Volume Selection box, for Use Existing Volumes of UR Pairs, select whether to use the volume used by the UR pair. If you are creating 3DC multi-target pair by three UR sites or cascade configuration pair, select Yes. If you are not, select No.

  7. In the Primary Volume Selection box, in LU Selection, select the Port ID and Host Group Name or iSCSI Target Alias to display the volumes from which you want to select the P-VOL.

  8. In the Available Primary Volumes table, select the volume that will be the P-VOL.

    NoteLimitations for Available Primary Volumes:
    • When you are using a virtual storage machine with, Available Primary Volumes displays physical LDEV information, not virtual.
    • Nondisruptive migration volumes are not displayed in Available Primary Volumes.

  9. In the Secondary Volume Selection box, for Base Secondary Volume, select the S-VOL’s Port ID, Host Group ID/iSCSI Target ID, and LUN ID.

    CautionFor USP V/VM and VSP, LUN IDs display in hexadecimal numbers. For VSP G1000, VSP G1500, and VSP F1500, 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.

  10. For Selection Type, select the method for assigning S-VOLs when multiple primary volumes are selected, Interval or Relative Primary Volume. See "Before you begin" for more information.

  11. For Mirror Selection, specify the following:

    1. For Master Journal, select a number from the list of registered journal IDs. The list excludes already-assigned master and restore journal IDs.

      NoteIf you selected Yes for Use Existing Volumes of UR Pairs in the Primary Volume Selection box, Depends on Selected P-Vols is selected for Master Journal.

    2. For Mirror ID, assign an identifier number for the mirror.

    3. For Restore Journal, select a number from the list of registered journal IDs. All journal IDs display (000-0FF).

    4. For CTG ID, select a consistency group from the list of those registered in the storage system. An asterisk indicates the CTG is assigned to a pair in the Select Pairs table.

  12. Click Options to define the following optional settings:

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

      - Entire 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.

      - Delta creates the delta resync pair but data is not copied to the S-VOL.

    2. For Initial Copy Priority, you can specify the scheduling order for this initial copy operation. Range is 1 to 256 (default = 32).

      If a time out error occurs, the copy operation may not be executed in the order that you set with Initial Copy Priority. The time out error may be caused by the CU configuration or a remote copy path error. Review the error, release the pair with the error, and then retry the Paircreate operation.

    3. In the Error Level list, you can select one of the following system responses if a failure occurs during this operation:

      - Mirror, to split all pairs in the failed pair’s mirror. Mirror is the default.

      - LU, to split only the pair that failed.

  13. When ready, click Add. This moves the new pair to the Selected Pairs table. (To remove a pair from the table, select the pair and click Remove).

  14. Click Finish.

  15. In the Confirm window, review the settings, enter a task name, and then click Apply.

Results

Based on the initial copy option you selected, you can verify that the pair status is correct in the Remote Replication window. The following table specifies the pair status required to successfully complete the operation.

Initial Copy Option

Pair Status Requirement

Entire or None

COPY or PAIR

Delta

HOLD, HOLDING

You can also monitor the progress of the operation by clicking File > Refresh in the menu bar. This updates the information in the list.

Parent Topic