LUN Manager rules, restrictions, and guidelines
Rules
In a Fibre Channel environment, up to 2,048 LU paths can be defined for one host group and up to 2,048 LU paths can be defined for one port.
In an iSCSI environment, up to 2,048 LU paths can be defined for one iSCSI target and up to 2,048 LU paths can be defined for one port.
Up to 255 host groups can be created for one Fibre Channel port.
Up to 255 iSCSI targets can be created for one iSCSI port.
In one LDEV of the ALU attribute, you can define the LU path to only one host group.
In one LDEV of the ALU attribute, you can define the LU path to only one iSCSI target.
Restrictions
You cannot define an LU path to journal volumes.
You cannot define an LU path to pool volumes.
When defining LU paths, you must not use Command Control Interface and Device Manager - Storage Navigator at the same time. If both programs are used simultaneously, operations can not be performed in the expected order and the storage configuration might be defined incorrectly.
If an LDEV of the ALU attribute is binding to LDEVs with the SLU attribute, the LU path cannot be removed.
You cannot define an LU path to the external volume of the data direct mapping attribute.
If an LDEV of the ALU attribute is binding to LDEVs with the SLU attribute, the LU path cannot be removed.
You cannot define an LU path to the external volume of the data direct mapping attribute.
You cannot define an LU path to an LDEV created from an accelerated compression-enabled parity group.
To define an LU path between a port and an LDEV that has the T10 PI attribute enabled, the port must have T10 PI mode enabled.
Guidelines
If you attempt to apply many settings in the LUN Manager windows, Storage Navigator might be unable to continue processing. Therefore, do not make more than 1,000 settings. Many settings are likely to be made when defining alternate paths (see Defining alternate LU paths), even though only two commands are required for defining alternate paths.
Do not perform the following when host I/O is in progress and hosts are in reserved status (mounted):
Remove LU paths (see Deleting LU paths)
Disable LUN security on a port (see Disabling LUN security on a port)
Change the data transfer speed for Fibre Channel ports
Change AL-PAs or loop IDs
Change the settings of fabric switches
Change the topology
Change the host modes
Remove host groups
Remove iSCSI targets
Set command devices