SWITCHBACK



SWITCHBACK

     Initiates the switchback of volume sets from the alternate system
     to the home system.  SPU Switchover/XL is not a part of the 900
     Series HP 3000 Computer System Fundamental Operating System and
     must be purchased separately.

SYNTAX


SWITCHBACK [FROM=]altsystem[[TO=]homesystem]

PARAMETERS


altsystem Indicates the name of the alternate system as
specified in the SYSGEN APAIR command. When
the operator enters the command
FROM=altsystem, all volume sets specified in
the configuration as belonging to homesystem
are switched back from altsystem and mounted
to homesystem. Altsystem can be operative or
inoperative when command is entered.

homesystem Indicates the name of the system whose home
volume sets were switched over to the
alternate system. When the operator enters
the command TO=homesystem, the switchable
volume sets specified in the configuration
that belong to homesystem are switched back
from altsystem and mounted on homesystem.

OPERATION


Before an operator can execute the command, you must
assign homesystem as the home system and altsystem as
the alternate system in the SPU configuration file.

If a hardware failure occurred, the operator must
enter the command from the home system console after
a successful reboot; the system is then ready to
receive the volume sets defined using the SYSGEN
utility AVOLSET command.

If a load balance was performed, no system reboot is
required.

The operator can enter the command within a session,
job, program, or in break mode.

The following requirement apply before an operator can
enter the SWITCHBACK command:

o The SPU Switchover/XL environment must be properly
configured using the SYSGEN utility SPU commands.

o The switchable nonsystem volume set must be closed on
the alternate system.

o The SWITCHOVER command must have been previously entered
from the alternate system.

o The operator must have OP or SM capability.

EXAMPLE(S)

      The following command is issued from the home system (Alpha)
      console as shown:

        SWITCHBACK FROM=BETA TO=ALPHA

      The home system (Alpha) responds by displaying the following
      message once on the home system (Alpha) and alternate
      system (Beta) consoles:

         /00:00/nn/SPU SWITCHBACK FROM BETA TO ALPHA STARTING.

      You must respond to the following message that is displayed
      on the home system (Alpha) when switchback has successfully
      completed:

         /00:00/nn/ACKNOWLEDGE SPU SWITCHBACK FROM BETA
         TO ALPHA COMPLETE (Y/N)?

         =REPLY nn,Y

      This message is displayed every 30 seconds until the operator
      acknowledges completion of the switchback.  The operator
      must respond to this message on the home system (Alpha).
      The reply has no effect except to stop the repeating message.

      The following message appears once on the alternate system
      (Beta) console:

          /00:00/nn/SWITCHBACK FROM BETA TO ALPHA COMPLETE.


Commands:  SPUCONTROL, SWITCHOVER

Manuals :  SPU Switchover/XL User's Guide (36378-90001)