OpenVMS fibre-channel restrictions

The restrictions listed in this section apply only if your DS6000™ licensed machine code has a version before 5.0.3.157. After these versions, the restrictions are removed.

Note: You can display the versions of the DS CLI, the Storage Manager, and the licensed machine code by using the DS CLI command ver –l.

The following restrictions are required for the DS6000 host adapter to maintain compatibility with the OpenVMS host system. Compatibility is enabled on a DS6000 adapter port after a defined host establishes fibre-channel connectivity to one or more storage unit volumes.

You must dedicate DS6000 adapter ports for only the OpenVMS type. It is recommended that each OpenVMS host adapter be in a fabric zone with one or more DS6000 adapter ports.
All DS6000 adapter ports that are in a fabric zone with an OpenVMS host adapter must have at least one DS6000 volume assigned to it. This can be the LUN 0 volume.
Multiple OpenVMS systems can access the same DS6000 adapter port. However, you must define each system for that specific DS6000 port and assign at least one DS6000 volume.
To re-enable compatibility, you can force the defined OpenVMS host to reestablish connectivity to the DS6000 adapter by disabling the switch port it is connected to, and then enabling the switch port again.

The following problems are a few examples of issues that might occur when you attach a storage unit to an HP AlphaServer OpenVMS host system without fulfilling the OpenVMS fibre-channel restrictions.

If the system hangs during boot

Your system might be attempting to access a host adapter port that is not configured for it. To correct your system, check to ensure that the following items are true:

The fibre-channel switch is enabled to ensure zoning.
The zones for the OpenVMS host are connected to only those ports that are correctly configured to support them.
Other fabric zones do not include the OpenVMS host adapters by mistake.

If the system reaches the mount verification timeout

All pending and future I/O requests to the volume fail. You have to dismount and remount the disk before you can access it again.

The mount verification process for fibre attached volumes might not complete until the system reaches the mount verification timeout. This can be caused by the same scenario that causes the system to hang during boot. Verify that the path to the affected volumes is available, and then follow the above list.

If another host system gains access to a storage unit host adapter port that is dedicated for OpenVMS

The port will have its compatibility mode disabled. This can occur when the fabric switch has disabled all zoning. After you reenable zoning, the storage unit port compatibility remains disabled. Some internal storage unit processes cause a momentary loss of connectivity to volumes with activity I/O. OpenVMS has no problems when the storage unit adapter port is in compatibility mode. If the mode is disabled, disk I/O could fail a read or write and display the following message:

-SYSTEM-F-TOOMANYRED, too many redirects

Force the host adapter to reestablish connectivity

Forcing the OpenVMS host adapter to reestablish fibre-channel connectivity with the storage unit adapter port will enable compatibility mode. You can force the connection only by disconnecting and then reconnecting one end of the physical fibre-channel cable between the host and the affected storage unit adapter port. You can also reestablish connectivity by accessing the fibre-channel switch and disabling one of the switch ports, and then enabling it again.