Advanced Topics › Configure Tape Devices Offline until CA MIA Synchronization

Configure Tape Devices Offline until CA MIA Synchronization

When sharing devices between multiple systems, there is an integrity exposure while devices are online to more than one system and CA MIA is not running. To avoid this, configure tape devices to be offline at IPL time, start CA MIA early in the IPL process to ensure that the product initializes and is fully functional when allocation begins on a system, and bring the tape devices online with VARY commands in the MIMSYNCH member.

To prevent devices from coming online automatically during IPL, we strongly recommend that you specify OFFLINE=YES on the IODEVICE macro used as input to the IOCP or MVSCP for devices to be shared. This tells z/OS to not allow devices to come online during the IPL.

If you are using the Hardware Configuration Dialog, then we strongly recommend that you specify YES for the OFFLINE parameter for the same reason.

The Hardware Configuration Dialog Define Device Parameters/Features panel provides the ability to configure devices as initially offline. The following is an example of this panel:

-------- Define Device Parameters / Features ----------
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Command ===> ____________________________Scroll ===> PAGE

Specify or revise the values below.

Configuration ID . : CONFIG01            OS/390 systems 
Device number  . . : 074A         Number of devices  : 1
Device type  . . . : Dummy 

Parameter/ 
Feature              Value    P Req. Description 
OFFLINE              Yes      Device online or offline
DYNAMIC              Yes      Device supports dyn config 
LOCANY               Yes      UCB can reside in 31 bit 

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To have CA MIA automatically bring devices online following system synchronization, you can place VARY ONLINE commands in the MIMSYNCH member of the MIMPARMS data set.

You can use the z/OS VARY ONLINE command or the CA MIA VARY ONLINE command, prefaced by z/OS MODIFY or the CA MIM command prefix character.

Note: For more information, see the CA MIM Programming Guide.

To prevent needless multiple executions of the VARY ONLINE command on any system, specify a scope of LOCAL on any VARY command that is to be executed on multiple systems. For example, specify a scope of LOCAL on VARY commands issued from a MIMSYNCH member shared by multiple systems.