If you create an SI pair during WriteSame or Unmap command processing, the pair creation might fail. In this case, create the pair again after the WriteSame or Unmap command processing finishes.Creating ShadowImage pairs
Creating an SI pair copies the P-VOL to the S-VOL.
If you create an SI pair during WriteSame or Unmap command processing, the pair creation might fail. In this case, create the pair again after the WriteSame or Unmap command processing finishes.
Before you begin
The P-VOL and S-VOL must be unpaired.
If the P-VOL is already paired with other S-VOLs (PAIR status), you have determined that the status of existing S-VOLs is the status that is required to create the new pair.
For more information about S-VOL status, see Unaffected S-VOL status and pair tasks.
If you are concerned with host server I/O performance, make sure that the I/O load is light.
For more information about checking I/O performance, see the Command Suite User Guide.
Procedure
In Command Suite:
On the Resources tab, click Storage Systems, expand the storage system tree, right-click the target storage system, and then select Local Replication.
In Device Manager - Storage Navigator:
In the Explorer pane, click Storage Systems, expand the storage system tree, and then click Replication > Local Replication.
In the Local Replication window, select the SI Pairs tab.
On the SI Pairs tab, click Create SI Pairs.
In the Select Pair Configuration window, complete the following steps, and then click Next:
For Copy Type, select ShadowImage.
For Emulation Type, select the emulation type.
For Pair Topology Type, select the pair topologies that match your configuration.
For more information about creating L1 and L2 pairs with different topologies, see Creating L1 and L2 pairs with different topologies.
For Split Type, select how you want to split the pair.
Values:
- Non Split: The pair is not split.
If you are simultaneously creating an L1 pair and an L2 pair, to prevent a failure and splitting the L2 pair before the pair is split (PSUS status), select Non Split.
- Quick Split (default): Splits the new pair, and then copies the data so that the S-VOL is immediately available for read and write I/O. The storage system copies the remaining differential data to the S-VOL in the background.
- Steady Split: Copies the differential data to the S-VOL, and then splits the new pair.
For Copy Pace, select the rate at which you want the storage system to copy data.
Values:
- Slower: Improved host server I/O performance but slower processing speed.
- Medium (default): Average processing speed and host server I/O performance.
- Faster: Faster processing speed but slower host server I/O performance.
The pace you select affects processing speed and host server I/O performance.
In the Select Primary Volumes window of the Create SI Pairs wizard, complete the following steps:
Optional: Filter LDEVs by port ID, host group name, or iSCSI target alias.
In the Available LDEVs table, select one or more LDEVs you want to be P-VOLs, and then click Add.
Nondisruptive migration volumes do not appear in the Available LDEVs table.
Selected LDEVs are moved to the Selected LDEVs table.
Click Next.
In the Select Secondary Volumes window of the Create SI Pairs wizard, assign LDEVs as S-VOLs to the specified P-VOL LDEVs.
If you specified one P-VOL, select a secondary LDEV from the Available LDEVs table, and click Set. Repeat this step to assign additional S-VOLs.
If you specified multiple P-VOLs, select an LDEV from the Available LDEVs table, select a P-VOL LDEV from the Selected Pairs table, and then click Set. Repeat this step as many times as needed to make all your pairings.
If you do not select a P-VOL from the Selected Pairs table, the S-VOL you select and set is assigned to P-VOLs in the order they are listed in the table.
Nondisruptive migration volumes do not appear in the Available LDEVs table.
After an S-VOL is selected, you can also perform the following optional steps:
To sort the Available LDEVs and Selected Pairs tables according to the capacity, choose a capacity item for Capacity.
The remaining number you have to select refers to the P-VOLs that do not have an assigned S-VOL, as seen in the Selected Pairs table.
To filter the Available LDEVs by a specific port ID, host group name, or iSCSI target alias, select Port ID, Host Group Name, or iSCSI Target Alias.
Select the Exclude Paired Volumes check box to exclude paired LDEVs from display.
To sort the Selected Pairs table, click Sort Pairs above the table.
To change the split type and the rate at which data is copied, which applies to all new pairs, change the pair options (see Changing ShadowImage pair options).
To change MU numbers, complete the following steps:
a. Select the line for the LDEV in the Selected Pairs table.
b. Click Edit Mirror Units.
c. In the Edit Mirror Units dialog box, specify the S-VOL's L1 and L2 mirror unit numbers, and click OK.
The pair topology is modified.
For more information about changing a pair's topology, see Creating L1 and L2 pairs with different topologies.
Change the pair options (see Changing ShadowImage pair options).
To remove an unwanted LDEV or pair from the Selected Pairs table, select the line for the LDEV or pair you want to remove and click Remove.
The pair's topology is refined.
Click Finish, and then confirm the settings.
Accept the default task name or enter a unique name.
You can enter up to 32 letters, numbers, and symbols, except the following:
\ / : , ; * ? " < > |
If you want to monitor the task after submitting it, select Go to tasks window for status.
Click Apply to submit the task.
The SI pair is created and the status is PAIR.
Related concepts
Related tasks