Limitations with SAP SFTP connection mode (SAP Note - 2401292 )

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Author : Jaspreet is a Senior Consultant with expertise in Service Delivery, Resource Management, Account Management, Project Delivery, Value Creation, Business Development and devising Strategic Road-Maps. Jaspreet has a range of cross industry IT experience with specialization in System Integration, SaaS, Cloud, Cyber Security, Data Science. He is seasoned in designing, developing, documenting, coding, modifying, testing and implementing business technology solutions.

Environment

 

SAP PO 7.4

 

Version

 

Service Pack:12

Release: NW731EXT_17_REL

 

SFTP Version

 

Adapter Type: SFTP http://sap.com/xi/XI/SFTP SFTP ADAPTER 1.0

1000.1.0.4.21.20160706043300

Problem Overview

/Demo/ does not exist

We migrated an interface from SAP PI 7.11 to SAP PO 7.4 and saw issues with the implementation of Advanced Mode Parameter (connection.mode.permanent). SAP SFTP component is not able to find Target SFTP Directory but with a “Catch”, continue to read on… The issue is with SAP support under “Very High” priority since June 2016.

Scenario requires us to transmit 1000s of files to print vendor. Receiving end is a CrushFTP’s (http://www.crushftp.com/index.html) SFTP site with username password authentication enabled.

 

Filename: %FileName%

 

Filepath: ~/Demo

 

Maximum concurrency: 30

 

Additional Parameters: connection.mode.permanent is set to “True”

 

Reason for setting the above parameter to “True” is because (SAP note 2069078) as per business process, we need to transmit 1000s of files during a set time frame. In order to do so, we enabled maximum concurrency so that file write processing can happen in parallel. Advance Mode parameter is set to “True” so that we do not overflow the maximum number of allowed active connection. If set to “False”, we will hit the SFTP server active connection threshold value and connection will be reset per below error and the most critical file transfer process will be halted. 

 

Transmitting the message to endpoint <local> using connection File_http://sap.com/xi/XI/System failed, due to: com.sap.engine.interfaces.messaging.api.exception.MessagingException: javax.resource.ResourceException: com.jcraft.jsch.JSchException: Session.connect: java.net.SocketException: Connection reset

 

However, if we chose to enable the connection.mode.permanent parameter the SFTP adapter will find the receiver end directory BUT only for the first single run of this interface. Next time, when the interface will run it will dump the error “directory does not exist”.

Analysis

 

After very detailed analysis and applying multiple fixes suggested by SAP support the issue still remains unaddressed.

 

SAP note :1737547

SAP note :1859563

'trackCacheUpdateXML'

 

SAP SFTP team is now working on this “very high” priority issue to isolate the problem with SFTP Adapter, Advanced Mode Parameter (connection.mode.permanenet) implementation, SAP note 2069078.

 

 

Workaround

 

We scheduled the effected channel to automatically stop/start once before the actual run of the scenario “interface” as we mentioned the transmission is fine in its first single run. So, every day we restart the channel as a temporary Band-Aid to work around this issue.

 

Conclusion

 

This blog will be updated with what fix we receive from SAP so that the other customers do not have to reinvent the wheel on similar issue.

Solution

This issue has been resolved by code changes to SAP SFTP adapter under SAP Note 2401292

2401292 - SFTP target directory not found when permanent connection mode is used

An advanced mode parameter 'check.resource.int' has been introduced. After setting the parameter 'check.resource.int' with value 'true', an additional check will be performed to ensure the existence of directory. The default value for the parameter  'check.resource.int' is false.

To get this correction available in your Support package you need to apply the patch matching to your support package version as per the instructions in the NetWeaver Support Package Stack guide which can be found on the SAP Service Marketplace as described in SAP Note 952402.