Tape IOGEN AUTOSWITCH setting with MIA

Products

• MIM Tape Sharing (MIA)
• MIM Data Sharing (MII)

Issue/Introduction

I noticed a little difference in tape ucbs IOGEN from one site to another –

Site 1. DEVICE (F000-F0FF)
           AUTOSWITCH=NO

Site 2.DEVICE (F000-F0FF)
          AUTOSWITCH=YES

 

What is the recommended setting for tape ucb AUTOSWITCH setting for MIA?

Is it ok to have AUTOSWITCH=YES for MIA?

Environment

Release : 12.5

Component : MIA

Resolution

MIM cannot be configured to utilize AUTOSWITCH. During startup, MIA examines the IOGEN attributes of all managed tape devices and if it detects AUTOSWITCH=YES it attempts to change it to no and produces MIM2154W MVS AUTOSWITCHING TURNED OFF FOR DEVICE dddd warning messages.

If MIA is unable to change the AUTOSWITCH to NO for whatever reason, it can cause the task to fail during initialization. The following message will be produced:
MIM2153E - Cannot manage autoswitchable device aaa

Changing the IOGEN to AUTOSWITCH=NO for all MIA managed devices will prevent potential problems.

Additional Information

The MIM documentation (MIA Programming) contains additional information in the section: Configure Tape Devices Offline until MIA Synchronization.

It explains why the IOGEN/HCD definition should be set to OFFLINE YES for MIA managed devices.