IBM Hyper-Scale Mobility is a powerful function for moving volumes between XIV Storage System systems in a manner that is transparent to host applications.
IBM Hyper-Scale Mobility is a feature of the XIV system. IBM Hyper-Scale Mobility enables clients to move a volume from one XIV Gen3 system to another in a manner that is indiscernible to host applications before, during, and after the volume migration.
IBM Hyper-Scale Mobility helps you with online data mobility, load balancing and over-provisioning.
XIV Storage System online volume migration is useful when combined with XIV Storage System thin provisioning, the volumes in the XIV thin pool that are unexpectedly using more hard space than planned can be moved to an XIV Storage System with plenty of hard pool space, with no effect on the application host severs.
IBM Hyper-Scale Mobility requirements
To cause minimal disruption to the host and uninterrupted I/O operations, these requirements must be met:
Multi-path driver. It is required that the host operating system uses a multi-path driver to access the volume that is being moved.
Switch zoning. Source and the destination XIV systems must be accessible to the host system concurrently.
Hyper-Scale Mobility process description.
The IBM Hyper-Scale Mobility process that is used to move a volume between XIV systems can be summarized in a sequence of stages.
The phases and states are depicted in the following picture:
The first stage of the IBM Hyper-Scale Mobility is to create the volume on the destination XIV Storage System, and to set up the relationship between the two volumes.
During migration, new data is written by the host to the source, and copied to the destination.
In proxy mode, the source no longer functions as a regular volume, and the source storage system communicates host requests to the destination. At this point, the migration is no longer reversible.
In proxy mode, the host can remain connected to the source without a need to zone and move it to the destination. The host can be moved after the ported volume data is on the destination.
The final stage of the migration involves connecting the host directly to the new volumen and the multi-path device driver must discover the new path to the ported volumen.
Finally, the original paths can be removed, and the IBM Hyper-Scale Mobility relationship can be deleted.
There are two ways of doing the mobility process, the first one is using the XIV GUI, or the command pront interface XIV CLI. In this case we are going to use only the GUI.
Using the XIV GUI Mobility
- Confirm that both the source and destination XIV systems are configured and accessible in the GUI.
Validate the host multipath.
Validate the host multipath connectivity to the source volume by running the xiv_devlist command of the XIV Host Attachment Kit.
Add the host to the destination XIV Storage System
Click the Hosts and Clusters link in the Hosts and Clusters menu on the destination XIV Storage System:
And then select the Add Host option:
After the host is added to the destination XIV Storage System, add the ports for the host.
Right-click the host entry and select the Add Port option:
After that we have to create the Hyper-Scale Mobility relationship, click the Volume Mobility link in the Remote menu, as shown:
Select the values for Source System, Master Volume, Destination System (Target), and Destination Pool
To immediately activate the IBM Hyper-Scale Mobility relationship upon creation, select the box “Activate Migration after creation”.
The Volume Mobility view for the source XIV Storage System now displays the new IBM Hyper-Scale Mobility relationship:
To complete the Migration task, perform the following step right-click and select the Step 1: Activate option, as shown in picture:
Proxy phase is successfully initiated, you are ready to map the newly created volume to the host on the destination XIV Storage System
After the destination volume is mapped to the host, you need to rescan the devices from the host. to discover the additional paths.
Run the xiv_fc_admin -R command, and then run the xiv_devlist command from the host.
After you have validated that the host has connectivity to the volume through the new paths to the destination you are ready to unmap the volume from the host on the source XIV Storage System, and remove the paths to the source volume from the host.
Click OK to unmap the source volume from the host.
Now that you have unmapped the volume from the host, you have lost paths.
Run the xiv_fc_admin -R command, and then run the xiv_devlist command from the host,
The final step is to end the proxy.
In the XIV GUI, go to the Volume Mobility view of the source XIV Storage System, Right-click the volume relationship and select the Step 3: End Proxy option:
The proxy has been removed, and you can confirm the expected end state of the volumes on both the source and destination XIV systems, the source volume is no longer on the source XIV Storage System and the destination volume exists on the destination XIV Storage System.