Periodically, IBM Support personnel will ask that customers send in their JLF file to aid in problem determination. The question arises from time to time on how to determine which JLF file is currently active, and how to send it in.
To determine which JLF file is currently active, you can issue the following command
which will show the DSN prefix being used, and then show any JLF archival files being used for ATF.
In the example above, VSAM DSN #1 is shown as active, which would indicate a suffix of I2ATF01. Combine that with the shown prefix, and you'll want to send in DSN=TSL2.DS620.I5421.I91A.I2ATF01
These are standard VSAM files, so normal IDCAMS REPRO jobstreams should successfully offload them for binary FTP to IBM Support.