You can configure the SAN so that all data LUNs are available to all clients (known as a uniform configuration) or so that only a subset of data LUNs are available to some clients (known as a nonuniform configuration). In nonuniform configurations, a client must be able to access all LUNs in any storage pool that has been used or can be chosen by a fileset that is used by that client.
If a client tries to read or write data on a LUN that it cannot access, SAN File System returns an I/O error to that client. If the client performs a file-system operation that only involves metadata (such as changing a directory, or listing or creating files), SAN File System does not return an I/O error because the operation does not involve the data LUN.
The active policy determines which storage pool is selected when a new file is created. In a nonuniform configuration, the policy must ensure that a newly-created file is allocated to a storage pool that is accessible to the clients that need the file. When you change the active policy, the new policy must meet this consistency property.
Parent topic: Clients
Parent topic: Planning the client configuration