Troubleshooting
Problem
A batch job is submitted that runs an FTP client session. The command input stream (INPUT DD) includes a request to transfer a tape data set (either GET or PUT). The request fails with an EZA2561W error allocating tape data set message, even though the FTP.DATA configuration has AUTOTAPEMOUNT TRUE specified.
Cause
Data set requests in FTP use dynamic allocation (DYNALLOC, SVC99) to obtain the referenced data set. However, tape data sets require that the associated volume be mounted on an available tape drive. If none are available at the time of the request, the allocation fails; which will cause the FTP step to fail as well.
Resolving The Problem
Add a DD to the FTP step's JCL to reference the requested tape data set. This will cause the normal job scheduling process to provide a tape unit for the step with the requested volume already mounted. Next, modify the FTP input command to reference the DD name instead of the data set name.
//TAPEDSN DD DSN=my.tape.data.set,UNIT=TAPE,
// VOL=SER=vvvvvv,DISP=(OLD,KEEP)
...
PUT //DD:TAPEDSN remote.file.name
Requests for tape mounts coming in by way of the FTP server are prone to the same problem of unit availability. Unfortunately, there is no equivalent technique for mounting the requested tape in advance. There is an existing requirement to add the ability to wait for an available unit to the dynamic allocation request, which is under consideration for a future release.
Related Information
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Document Information
Modified date:
15 June 2018
UID
swg21216840