Using external volumes
Create external volumes by mapping volumes of the external storage system that is connected to the port of the local storage system.
For storage systems of the VSP 5000 series, if the port on the local storage system is a target port, you need to change that port on the local storage system to a bidirectional port.
The workflow is shown in the following diagram.
- Create volumes in the external storage system
- Create volumes in the external storage system. If the external storage system supports the REST API, you can use the REST API on the external storage system to create volumes.
- Configure the ports of the external storage system
- Configure the ports of the external storage system and the system options. For details on how to configure the ports and options, see the manual for the external storage system that you are using.
- (for iSCSI) Get information about the iSCSI target of the port on the external storage system
- If the external storage system is connected via an iSCSI connection, retrieve information about the iSCSI target of the port on the external storage system.
- (for iSCSI) Register the iSCSI name of the port on the external storage system to the port on the local storage system
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If the external storage system is connected via an iSCSI connection, register the retrieved iSCSI name of the port on the external storage system to the port on the local storage system.
After registering the iSCSI name, use the API request for performing a login test make sure that you can successfully log in.
- (for iSCSI) Get the iSCSI name of the external storage system, that was registered to the port on the local storage system
- If the external storage system is connected via an iSCSI connection, get the iSCSI name of the port on the external storage system, that was registered to the port on the local storage system.
- (for iSCSI) Perform a login test for the iSCSI target of the external storage system, that was registered to the port of the local storage system
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If the external storage system is connected via an iSCSI connection, test whether you can log in to the iSCSI target of the external storage system by using the retrieved iSCSI name.
If you cannot log in, revise the settings so that you can log in, or delete the iSCSI target. If you do not delete iSCSI targets that cannot be used to log in, when you retrieve information about iSCSI targets of the port on the external storage system, there will be an increased load on the network or external storage system and information might not be retrieved successfully.
- Get the list of the ports of the external storage systems
- Get information about the ports of the external storage systems that are connected. The obtained information will be used to map external volumes.
- Get the list of LUs defined for the port on the external storage system
- Get information about the LUs that are defined for the ports of the connected external storage system. The obtained information will be used to map external volumes.
- Get information about the external path group
- To use an existing external path group to perform mapping, get information
about the external path group and check the path group ID.
When an iSCSI connection is used and the model of the local storage system is VSP E series, VSP G350, G370, G700, G900, VSP F350, F370, F700, F900, you can perform this operation by using the Platform REST API (Simple). For detailed information about this operation, see the Hitachi Storage Advisor Embedded Guide on the Hitachi Vantara Knowledge website. For storage systems of other models, use storage management software such as CCI.
- Map the external volumes
- Create external parity groups, and register information about the external
volumes of the external storage system that you want to map. Check the registered mapping
information with the API function for getting information about the external path group to
which the parity groups that you created belong.
When an iSCSI connection is used and the model of the local storage system is VSP E series, VSP G350, G370, G700, G900, VSP F350, F370, F700, F900, you can perform this operation by using the Platform REST API (Simple). For detailed information about this operation, see the Hitachi Storage Advisor Embedded Guide on the Hitachi Vantara Knowledge website. For storage systems of other models, use storage management software such as CCI.
- Create volumes
- Create external volumes from the external parity groups that have been created in the local storage system. The created external volumes can be allocated to the host or used as pool volumes (this is the same as other volumes in the local storage system).
Making the external paths redundant
You can make the access routes to the external volumes redundant by setting multiple external paths between the local storage system and the external storage system. To set multiple external paths, add the paths to the external path group. The external path group is created automatically when external volumes are mapped.
The workflow is shown in the following diagram.
- Get information about the external path group
- Get information about the target external path group to check the path
group ID.
When an iSCSI connection is used and the model of the local storage system is VSP E series, VSP G350, G370, G700, G900, VSP F350, F370, F700, F900, you can perform this operation by using the Platform REST API (Simple). For detailed information about this operation, see the Hitachi Storage Advisor Embedded Guide on the Hitachi Vantara Knowledge website. For storage systems of other models, use storage management software such as CCI.
- Add external paths to the external path group
- Add external paths by specifying the external path group.
Changing priorities of external paths
The priorities of external paths depend on the order that the paths are registered to the external path group. To change the priority of a path in the REST API, delete the paths that are registered before the path for which you want to increase the priority, and then re-register the paths.
The workflow for external paths is shown in the following diagram.
- Get information about the external path group
- Get information about the target external path group, and check the
priorities of the external paths and the path group ID.
When an iSCSI connection is used and the model of the local storage system is VSP E series, VSP G350, G370, G700, G900, VSP F350, F370, F700, F900, you can perform this operation by using the Platform REST API (Simple). For detailed information about this operation, see the Hitachi Storage Advisor Embedded Guide on the Hitachi Vantara Knowledge website. For storage systems of other models, use storage management software such as CCI.
- Delete the external path from the external path group
- From the external path group, delete the external path whose priority you want to reduce.
- Re-register the external path to the external path group
- Re-register the deleted external path in the external path group. To add more than one path, re-register the paths starting from the path with a higher priority.
Abolishing the use of external volumes
To dispose of an external storage system, disconnect the external volumes to release the mappings, and abolish the use of the external volumes.
The workflow is shown in the following diagram.
- Disconnect the external volumes
- Disconnect the external volumes. Input operations to and output operations from the mapped external volumes are stopped, and the data stored in the cache memory is written (destaged) to the external volumes.
- Release the mappings with the external volumes
- Delete the external parity groups to release the mappings with the external volumes. Data that has been written to the volumes on the external storage system site is not deleted after mappings are released. When the last external parity group in the external path group is deleted, the path group is automatically deleted.
- (for iSCSI) Delete the iSCSI name of the external storage system, that was registered to the port on the local storage system
- If the connection to the iSCSI target is no longer necessary, delete the iSCSI name of the external storage system, that was registered to the port on the local storage system.