Using Scan Host Groups to Migrate Information

When migrating host information, it's important to understand how the Scan Host Groups feature functions depending on the environment parameters:

• If you select multiple storage systems, server creation runs in ascending order of the storage system serial number. The management software ignores host groups without WWNs because it only sees host group configuration and cannot determine whether a host group contains WWNs of clustered servers.
• The management server cannot have both FC and iSCSI protocols. Different protocols in host groups result in different servers. If the host mode conflicts between host groups, the software creates only one server based on the host group found first.
• When the management software finds a host group with an external array connection and both storage systems are already onboarded, the host groups are ignored. If only the external storage system is onboarded, the software creates a server. (There is no way to check whether the host group is used by an external array or a host.) For host groups with the same WWNs set, the software creates a single server. Even if the name of each host group is different, they are treated as a single server.
• The management software determines the port to use when attaching the volume to the newly created server. If the same WWN is found in multiple host groups during a single scan, the result depends on the order of storage systems in the scan.

In addition, be aware of the following WWN-related information:

• You may need to edit the mapping between servers and WWNs after scanning completes.
• If a server already exists with the same WWNs as scanned host groups, the software does nothing.
• The software adds newly found WWNs to existing servers if the server name and host group name are the same.
• The software creates a new server with the scanned WWNs if there is no matching server name and the host group contains WWNs that no other existing servers use.
• Existing servers are never deleted (new WWNs may be added, but there is no WWN removal or server deletion).
• If host groups over multiple storage systems are scanned and the host groups have volumes provisioned from each storage system:
  • After scanning both storage systems, the software creates a server from the host groups over the multiple storage arrays.
  • A scan reconciles servers and host groups based on a set of WWNs in each host group.