Local Replication

This help page provides information to guide you through the tasks and procedures to manage local replication with Navigator 2. It contains the following topics:

Overview (back to top)

Local replication is performed using either ShadowImage or SnapShot. These products allow you to create a copy of a volume (Logical Unit) in the array. You can create an actual copy of a volume by using ShadowImage and can create a virtual point-in-time copy of a volume by using SnapShot.

ShadowImage and SnapShot treat the source volume (called Primary Volume, or P-VOL), and its copy, (called Secondary Volume, or S-VOL), as a volume pair. For example, you can a copy by creating a pair.
ShadowImage and SnapShot are optional functions and require licenses.

Setting up for Local Replication (back to top)

To set up local replication using ShadowImage or SnapShot, consider the following:

For ShadowImage, it is necessary to set up management ports that you plan to use as a Secondary Volume (S-VOL)
For SnapShot, it is necessary to create logical units that to as volumes for a data pool. You must also creaste a data pool and snapshot logical units.

Managing Data Pools (back to top)

A data pool is a logical entity that can contains one or more logical units. A secondary SnapShot volume is a virtual volume that contains actual data from the primary volume and differential data stored in one or more data pools.

Managing data pools primarily includes creating data pools and adding logical units to them. Note that you cannot create a snapshot pair until after you have created a data pool that includes at least one logical unit. You can add logical units to an existing data pool to expand its capacity, even if snapshot pairs using that data pool have already been created.

One data pool can handle differential data of multiple primary volumes and multiple secondary volumes. For example, when two secondary volumes of one primary volume and three secondary volumes of another primary volume are created, the differential data can be stored in one data pool.

Displaying Data Pool Information

The list of Data Pool provides the following information about each data pool.

Item	Description
Number	This field displays ID of the Data Pool.
Capacity	This field displays the total capacity in the Data Pool.
%Used	This field displays the rate of usage capacity to the total capacity in the Data Pool.
Threshold	This field displays the rate being set to the Data Pool as High water mark. If %Used over this threshold, status of the Data Pool and pairs that use this Data Pool.
Status	This field displays shows the status of Data Pool. Each status mean are described below. Normal: Shows that the %Used is less than the set threshold. Threshold over: Shows that the %Used of the pool exceeds the set threshold. If you leave this status, the possibility that data of SnapShot Logical Unit lost cased by shortage of the Data Pool becomes high.

To display the logical units the in the data pool, double click the number of the data pool.
To add logical units to a data pool or change the threshold, click Edit Data Pool. The Edit Data Pool window is displayed.

Creating a Data Pool (back to top)

To create a data pool:

In the Data Pools window, click Create Data Pool.
Optional step: To change the default settings, enter the appropriate information in the Data Pool number and Threshold fields.
Click the to the left of the logical unit that you have created for making up this data pool in LUs list box.
Click OK to use these settings and continue, or Cancel to exit without creating a data pool.
When the data pool has been created, a message box is displayed. Click Close to exit the window and go back to the Data Pools window. You should now be able to see the new data pool listed in the window.

See the Create Data Pool help page for more information.

Adding Logical Units to a Data Pool (back to top)

To add a logical unit to a data pool:

In the Data Pools window, click the check box to the left of the data pool to which you want add logical units and click Edit Data Pool.
Click the to the left of the Logical Unit that you want to add to the data pool in LUs list box.
Click OK to use this setting and continue, or Cancel to exit without adding logical units.
When logical units has been added, a message box is displayed. Click Close to exit the window and go back to the Data Pools window. You should now be able to see that the Capacity of the data pool is grown.

See the Edit Data Pool help page for more information.

Changing a Data Pool Threshold (back to top)

To change the threshold rate:

Click the check box to the left of the data pool that you want to add logical units and click Edit Data Pool in Data Pools window..
Enter value that you want to set as threshold rate in the fields of Threshold.
Click OK to use these settings and continue, or Cancel to exit without adding logical units.
When the threshold rate has been changed, a message box is displayed. Click Close to exit the window and go back to the Data Pools window. You should now be able to see that the Threshold of the data pool is changed.

Deleting a Data Pool (back to top)

To delete a data pool:

In the Data Pools window, click the to the left of the data pool that you to want to delete. Then click Delete Data Pool.
When the data pool has been deleted, a message box is displayed. Click Close to exit the message box and go back to the Data Pools window. You should now be able to see that the data pool is not listed in the window.

NOTE: A data pool that is being used by a snapshot pair cannot be deleted.

Managing SnapShot Logical Units (back to top)

The SnapShot Logical Unit is virtual volume and it is specified as secondary volume of SnapShot when you create a pair.

Displaying SnapShot logical units

The list of SnapShot Logical Unit provides following information about each SnapShot Logical Unit.

Number	This field displays LUN assigned to the SnapShot Logical Unit.
Capacity	This field displays capacity that is prepared virtually. When you create pair, you can select as the secondary volume only the SnapShot Logical Unit whose capacity is same as primary volume.

Creating a SnapShot Logical Unit (back to top)

To create a SnapShot Logical Unit:

Click Create SnapShot LU in SnapShot Logical Units window.
Enter the number that you assign for the SnapShot Logical Unit in the fields of LUN.
Enter the capacity of primary volume that you plan to create pair with this SnapShot Logical Unit in the fields of Capacity and select the unit from the drop-down list.
Click OK to use these settings and continue, or Cancel to exit without creating a Data Pool.
When the SnapShot Logical Unit has been created, a message box is displayed. Click Close to exit the window and go back to the SnapShot logical units windows. You should now be able to see the new SnapShot listed in the window.

Deleting a SnapShot Logical Unit (back to top)

To delete a SnapShot Logical Unit:

Click the check box to the left of the SnapShot Logical Unit and click Delete SnapShot LU in SnapShot Logical Units window.
When the Data Pool has been deleted, a message box is displayed. Click Close to exit the window and go back to the Data Pools window. You should now be able to see that the SnapShot Logical Unit is not listed in the window.

NOTE: You cannot delete a SnapShot Logical Unit that has been specified as an
S-VOL.

Managing Pairs (back to top)

This section provides information on how to create and manage pairs.

Displaying Pair Information

The list of Pairs provides following information about each pair. To display the latest information click Refresh.

Pair Name	This field displays pair name, if attached.
Primary volume	This field displays LUN of primary volume.
Secondary volume	This field displays LUN of secondary volume.
Status	This field displays the status of the pair. Each status mean are described below. Synchronizing: The pair is in process of copying data from primary volume to secondary volume. Reverse Synchronizing: The pair is in process of copying data from secondary volume to primary volume. Paired: Modification to data to primary volume is reflected to secondary volume automatically. Split: Secondary volume has become backup of primary volume. Threshold over: The shortage of the Data Pool that the pair uses almost occur. If the shortage occurs the data of secondary volume is lost. Failure: A failure occurs and maintenance of Arrays might be needed.
Progress Rate	This field displays the progress of the operation.
Copy Type	This field displays ShadowImage or SnapShot.
Group Number	This field displays number of the group that the pair belongs to.
Group Name	This field displays name of the group that the pair belongs to, if the group have a name. If the pair does not belong to any group, "Ungroup" is displayed.
Backup Time	This field displays the time when you backup the primary volume to secondary volume by splitting pair.
Split Description	This field displays a description that you wrote to identify the backup.

To display the detail information, click the pair name. The following information is provided in addition.

Capacity	This field displays the capacity of the primary volume.
Data Pool Number	This field displays the number of the Data Pool that the pair uses to store differential data If the Copy Type is SnapShot.
Copy Pace	This field displays the copy pace of synchronizing and reverse synchronizing.

Creating a Pair (back to top)

The following sections provide details necessary to create a replication pair.

NOTE: With ShadowImage, the time required for the initial copying of data, after creating the pair, from the primary to the secondary volume depends on the amount of data in the primary volume. The entire volume is copied, block for block, to the secondary volume.

Prerequisites for Creating a Pair

Before you attempt to create a pair, ensure that at least two logical units (volumes) have already been created. If the pair has been created and its status is set to Paired, secondary volume becomes copy of its primary volume and is synchronizes with the primary volume.

Procedure for Creating a Pair

To create a pair:

In the Arrays window, select the array on which to create a pair and then click Show and Configure. The Array window and Explorer tree are displayed.
In the Explorer tree, expand the Replication menu and select Local Replication.
In the Local Replication window, ensure that the Basic tab is displaced.
In the Basic tab, click Create Pair.
In the Copy Type field select either ShadowImage or SnapShot. The volumes listed in the Primary volume and Secondary volume list boxes change according to the selected function.
In the Pair Name field, enter a name.
Select a primary volume and a secondary volume. Both the primary and secondary volumes must be the same size.
If you selected SnapShot as the Copy Type, select the Data Pool in the Data Pool number drop-down list.
If you do not need to change anything in the Advanced Settings tab, skip steps 10 - 13. Otherwise, click the Advanced tab.
In the Advanced tab, select Group Number or Group Name if necessary.
Select a Copy Pace from the drop-down list.
To change the default settings, click the check box below the list. You can also configure Allow that provides Read access to the S-VOL after the pair is created, or Split automatically to split the pair immediately after it has been created.
Click OK to save the setting and continue, or Cancel to exit without creating a pair.
In the displayed message box, read the confirmation and warnings, then click the to the left of the text to agree.
Click Confirm to continue or Cancel to close the window and exit without creating a pair.
When the pair has been created, a message box is displayed. Click Close to exit the window and go back to the Local Replication window. You should now be able to see the new pair listed in this window.

Deleting a Pair (back to top)

To delete pair:

Click the check box to the left of the pairs that you want to delete and click Delete Pair in Pairs list.
In the displayed message box, read the confirmation and warnings and click the check box to the left of sentence to agree the confirmation and Click Confirm to continue or Cancel to close the window and exit without deleting pairs.
When the pair has been deleted, a message box is displayed. Click Close to exit the window and go back to the Local Replication window. You should now be able to see that the pair is not listed in the window.

Splitting a Pair (back to top)

To split a pair:

Click the check box to the left of the pairs that you want to split and click Split Pair in the Paris list.
Enter a description to identify the backup, if necessary.
If the Copy Type is ShadowImage, click the check box to split and change the pair status to Failure.
If the Copy Type is ShadowImage, click the check box to select Quick Mode. Quick Mode automatically creates and formats the LU and also creates the pair.
Click OK to continue or Cancel to close the window and exit without splitting pairs.
When the pair has been split, a message box is displayed. Click Close to exit the window and go back to the Local Replication window. You should now be able to see that the pair status is changed to Split in the Pairs list.

Re-synchronizing a Pair (back to top)

To re-synchronize a pair:

Click the check box to the left of the pairs that you want to re-synchronize and click Resync Pair in the Paris list.
If the Copy Type is ShadowImage, click the check box to select Quick Mode. Quick Mode automatically creates and formats the LU and also creates the pair.
In the displayed message box, read the confirmation and warnings and click the check box to the left of sentence to agree the confirmation and Click Confirm to continue or Cancel to close the window and exit without re-synchronizing pairs.
When the pair has been re-synchronized, a message box is displayed. Click Close to exit the window and go back to the Local Replication window. You should now be able to see that the pair status is changed to Paired or Synchronizing in the Pairs list.

Editing Pair Information (back to top)

To edit the description of a pair of volumes:

In the Arrays tree, select Replication > Local Replication. The Local Replication window is displayed. The window contains a table showing all of the pairs that have been created for he selected array.
In the table, click the check box to the left of the name of the pair whose settings you want to change.
Click Edit Pair. The Edit Pair dialog box is displayed.
As needed enter a new name or edit an existing name in the Pair Name field.
As needed, enter a new name or edit an existing name in the Group Name field.
As needed, select a copy pace (speed) from the drop-down list of available speeds.
Click OK to continue or Cancel to close the window and exit without editing pair information.
When the pair information has been changed, a message box is displayed. Click Close to exit the window and go back to the Local Replication window. The Replication window displays the updated pair information.

Restoring the Primary Volume from the Secondary Volume (back to top)

To restore the primary volume from a secondary volume:

Click the check box to the left of the pairs that you want to restore primary volume from secondary volume and click Restore Pair in the Paris list.
In the displayed message box, read the confirmation and warnings and click the check box to the left of sentence to agree the confirmation and Click Confirm to continue or Cancel to close the window and exit without restoring primary volume from secondary volume.
When the primary volume has been restored, a message box is displayed. Click Close to exit the window and go back to the Local Replication window. You should now be able to see that the pair status is changed to Paired or Reverse Synchronizing in the Pairs list.