7. Metro Based Non Disruptive Migration

Learn about NDM and the enhancements made in the latest release including leveraging SRDF/Metro for NDM

Migrate an Application using Metro Based NDM

In this lesson we will explore how to migrate an application leveraging Metro Based NDM

If you are starting the lab with this section, you will have to first login to the Unisphere UI. Double-click **U4V Demo** icon on the desktop. Login to **Unisphere** with the following settings: - Username: **smc** - Password: **smc**

From the **Overview** page locate the array **000120200107**, this will be the source array and **000197900049** will be the target array for both migrations to be carried out. Click on the source array **107**

Navigate to **Data Protection** then **Migrations** on the left hand pane

Before starting any non disruptive migration it's important to verify that migration environment has been created and is healthy. A migration environment is a special SRDF group used specifically for Non disruptive migration of data.

Click on the **Environments** tab. In this demo, ahead of time, the necessary NDM environment to the target array ending **049** has been created. The state shows the Environment is in a healthy state and ready for new Migrations. The **In Use** flag suggests there is an NDM session using this particular environment already. There is a session Pre-set to highlight this feature.

Now that the Migration environment has been verified, we are confident everything is in place to start a non disruptive migration of an application and it's Data. We will be migrating the **VM_datastores** storage to array **000197900049**.

From the **Storage Group** list select the filter button and enter **VM_d** to filter the list and find the **VM_datastore** storage group

Select the **checkbox** for **VM_datastores**, to highlight the storage group to be migrated.

From the three vertical dots icon select **"Migrate"**

Ensure that array **000197900049** is selected and click **"Next"**

Select **"SRP_1"** as the storage pool on the target array. Click **Next**

Review the **Masking View** information, at this point the user has the option to rename or select different ports on the target array, useful if you are want to adopt new naming standards or add additional ports. For the demo we will simply accept the defaults. Click **Next**

Lastly review the Migration Summary, and click **Run Now.**

The migration session has now begun, all necessary devices and masking structure is now in place for the host to access the application data on the new array. If the precopy option was selected data has already started transferring. Click **OK**

At this point the migration is in progress, depending on the operating system the host administrator may need to do a SCSI rescan to pick up the paths to the new storage array.

Select **Data Protection -> Migrations** on the left hand pane

Back in the **Sessions** tab, the **VM_Datastores** SG is showing as **Synchronized**. Two things have happened to make this possible: - The data from the source has fully transferred to the target. - All hosts involved in the migration have been rescanned . The rescan allows the system to pick up the new paths to the target array and with the automatic orchestration of the Masking view on the target array we are now full active/active to source and target from the application server. The new volumes on the target array appear as additional paths to the existing device, host multipathing will include them in the data access paths. This is due to the WWN spoofing that allows our Non Disruptive Migraiton feature to operate seamlessly,

To finalize the migration we need to Commit it. Select **VM_datastores** and click **Commit**.

Click the **"Cleanup"** field. Click **Run Now**

Click **"OK"**

The migration is now complete. Access to the original volumes has been removed and all structures and storage objects related to the original masking view have been removed once they are not shared with any other masking view.

The SG is removed from the **Data Protection > Migrations > Sessions** list signifying the SG has been migrated successfully

Lets change the focus of Unisphere to the Target Array **"000197900049"** Do this by changing the array from the top banner - select **"000197900049"** from the dropdown

Just like earlier in the lesson from the **storage groups** view on array **000197900049** you can see the the new storage group is present with the same number and configuration of devices containing the migrated data. Select **Storage > Storage Groups** and scroll to find **VM_datastores**

Select **VM_datastores** Note in the additional details view the masking view has been created on the target array.

It really is that easy, the migration wizard for PowerMax Non Disruptive migrations guides you seamlessly through a migration with little user interaction required. These steps can also be orchestrated through the PowerMax REST API should you with to automate the entire process.

Congratulations! You have reached the end of the Metro Based Non Disruptive Migration lesson. If you want to learn more or dive deeper into the technologies involved be sure to check out the white papers available on infohub [here](https://infohub.delltechnologies.com/en-us/t/dell-emc-powermax-and-vmax-non-disruptive-migration-best-practices-and-operational-guide-1/) Click **Close** in the top left corner of this script to return to the demo guide.