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VARY tape drives using IFSYS and NOTAVAILABLE in MIA to limit systems with access

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Article ID: 188724

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Updated On:

Products

MIM Tape Sharing (MIA) MIM Resource Sharing (MIM)

Issue/Introduction

We need advice on the below mentioned scenario.
 
We have few drives (eg: 5BE* AND 5BF*)  synced across all the Production Lpars. But here comes the request for us that it should be synched only in 2 Lpars (PRD1/2 - where the devices has logical paths) and get it out of all other production Lpars.
Another expectation in this scenario would be as follows:
Now we see these drives as ON for PRD1/2 Lpars, and other productions Lpars we see it as OFF when issued MIM display command on the devices. So now we except it should show ON only for PRD1/2 and rest of the production Lpars as 'Not available' when we display the Status of devices.

-config is shared across all LPARS.

Configuration:
The MIMINIT shows
COMMANDS=MIMCMNDS,  
COMMUNICATION=DASDONLY,
COMPATLEVEL=12.0,    
DEVCLASS=NONE,      
DEVLIST=MIMUNITS,  
MODE=DEMAND,        
MIMPLEX=MIMPLEX,    
QNAMES=MIMQNAME,
SAFCMDAUTH=OFF,      
SAFPREFIX=MIMGR,    
SIGNON=YES,          
SUPPRESSRESP=YES,  
SYNCH=MIMSYNCH,      
RESTARTSYNCH=MIMSYNCH
 
MIMUNITS has a medium sized list that ends with
5DD*
5BE*
5BF*

MIMSYNCH varies everything online, ending with
@VARY  5D00-5DDF,ONLINE
@VARY  5D00-5DDF,PREF=NONE 
@VARY  5BE0-5BEF,ONLINE    
@VARY  5BE0-5BEF,PREF=NONE 
@VARY  5BF0-5BFF,ONLINE    
@VARY  5BF0-5BFF,PREF=NONE
 
 

Environment

Release : 12.5

Component : MIA

Resolution

1. Change the MIMSYNCH member to VARY the tape devices for 5BE* and 5BF* ONLINE only for the desired systems.

IFSYS PRD1,PRD2    
@VARY 5BE0-5BEF,ONLINE  
@VARY 5BE0-5BEF,PREF=NONE
@VARY 5BF0-5BFF,ONLINE  
@VARY 5BF0-5BFF,PREF=NONE
ENDIF                    

the devices will be varied online for PRD1 and PRD2.

2. Change the MIMSYNCH member to VARY these same tape devices NOTAVAILABLE on all systems where they should not be available:


IFSYS TST1,DEV1,DEV2,TST2,PRD3,USL1,TCP1,IMS1
@VARY 5BE0-5BEF,NOTAVAILABLE
@VARY 5BF0-5BFF,NOTAVAILABLE
ENDIF

This allows all tape drives to be handled uniformly across all systems, but only be available on PRD1 and PRD2.

Without these additional statements, the devices would show as OFFLINE for all other systems.
That means they would show up in the OFFLINE list of devices for all other systems, and operations may try to VARY them online on one of those systems.


Change will be implemented automatically at IPL time.

The MIM VARY xxx NOTAVAILABLE command can be issued dynamically to make the change immediately on the systems where this status needs to be implemented sooner.

Additional Information

Note:  All VARY commands can be defined in the MIMSYNCH to be issued as MIM commands
          VARY commands outside of the basic VARY device,ONLINE | OFFLINE must be issued as MIM commands, not MVS, as MVS will not be able to handle the additional parameters and the VARY command will fail.

If you are using a different CMDPREFIX, use that instead of '@'.
If you are not using a prefix, define the complete command:  MIM VARY.....