Creating Virtual Volume Mirrors

Before creating mirrors, review About Mirroring and High Availability and Best Practices for Mirroring for information about mirror types and to understand the mirror terminology used in SANmelody software. You can create mirrors from either of the storage server partners.  

 

IMPORTANT:  Mirror path configurations, such as using specific mirror paths or redundant mirror paths, must be configured before creating a mirror. After a mirror configuration exists for a virtual volume, mirror path settings cannot be changed. Refer to Specifying the Mirror Path to configure before creating mirrors.

 

In order to create a mirror, you need the following:

  • An HA partnership established between two storage servers. See Establish an HA Partnership.

  • Linear virtual volumes must be created on the storage server to be designated as the primary. See Creating Linear Virtual Volumes, if necessary.

  • Ensure that you have available volumes on the storage server to be designated as the secondary. (See lower-right pane of the Storage Server snap-in.)

To create a virtual volume mirror:

  1. Ensure the storage server is in Read/Write mode so that you can configure.

  2. From the SANmelody snap-in, select the Virtual Volumes or Application Servers snap-in.

  3. Select a previously created linear virtual volume in the right pane and select Set Mirror from the shortcut menu to open the Partner Volume Selection box. (The linear volume selected is referred to as the primary volume and the storage server from where the linear was created is referred to as the primary server.)

As you create mirrors, for load balancing It is a good practice to create mirrors using both storage server partners as primary servers, instead of creating all your mirrors using only one storage server as the primary server.

  1. In the Partner Volume Selection box, select a volume from the list of available volumes on the partner server to use as the mirror (or secondary volume) in the virtual volume.

SANmelody partnervolumeselection2 Creating Virtual Volume Mirrors

Only legitimate candidate volumes will be displayed. If you choose a secondary volume that has a different size than the primary volume (either larger or smaller), the size of the resulting mirror set will be the smaller of the two.

  1. In the Mirror Type area, select the type of mirror you wish to create:

    1. Standard – uses a single path.

    2. Alternate Path (AP) – used for the DataCore AP product on the application server. Select Bootable to define volumes as having a bootable operating system.

    3. 3rd Party Alternate Path/MPIO (3PAP) – used for the DataCore MPIO product and qualified 3rd party AP products on the application server.

    4. Cluster Path (CP) – used for cluster-enabled application servers, such as HACMP or Windows 2000 Clusters.

  2. In special cases, it may be necessary to replace static volumes (partition-based volumes or static NMVs) with dynamic NMVs, or dynamic with static. Refer to Allow Mixed Static and Dynamic Mirrors before enabling the Allow Mixed Static and Dynamic Mirrors check box.

  3. Click OK to complete your choices and close the dialog box. In the Virtual Volumes snap-in, the mirror icon to the left of the virtual volume in the right pane appears in red until you apply the configuration.

  4. Mirror mappings cannot be changed after the configuration is applied. To ensure that mirror mappings are using the desired channels review the mirror mappings under the Mapping tab in the Virtual Volume Properties, see Mapping Properties.

  5. Apply your configuration by clicking the Apply icon SANmelody applyicon Creating Virtual Volume Mirrors on the toolbar to change the original linear virtual volume to a virtual volume mirror. The mirror will begin to synchronize so that the data on both volumes in the mirror are identical.

 

Related Topics:

Splitting a Mirror

Revert to Standard Mirror

Replacing a Volume in a Virtual Volume

Specifying the Mirror Path

Creating Virtual Volume Mirrors