XCOM using UNC/NAS share "XCOMN0416E Error writing output file: Bad file descriptor"

Products

• XCOM Data Transport - Windows
• XCOM Data Transport

Issue/Introduction

Files are transferred to/from the Mainframe via XCOM proxy server before they go to the final XCOM server destination.
File transfer to XCOM for Windows using UNC/NAS share for the remote file.
Seeing recent problem where approximately 1 in 1,000 files or one per day is not transferring correctly and receiving partial files. Requiring them to be resent from our mainframe team. The xcom.log has this error:

XCOMN0416E Error writing output file: Bad file descriptor

The file should normally come down in seconds not 20mins and fail. The issue seems to be impacting files over about 2MB.

Environment

Release : 11.6

Component : XCOM Data Transport for Windows

Resolution

1. Support initially suggested perhaps there is a transient problem with writing to the Windows UNC/NAS share directory for the remote file creation?

2. From customer's xcom.gb file, XCOMLOG is also configured to write xcom.log into the same network share as the received files.
Change the parameter XLOGFILE in xcom.glb to store the xcom.log file at any other share location or on the local server for some time period to see if the problem is resolved.
The default value for parameter XLOGFILE is %XCOM_HOME%\xcom.log which stores the xcom.log file at XCOM install directory.
NOTE: The XCOMD service needs to be restarted after making xcom.glb changes.

The errors went away without making any changes. It is suspected they were network-related and due to the way the XCOM Proxy is configured.

Additional Information

It is possible that multiple parallel UNC connections to such a location are causing the problem if the UNC settings are not configured properly.
The registry value IRPStackSize can be increased to try to help with this.