SAP PI Server creating multiple sessions with target SFTP
We have a setup from SAP PI (7.11 SP6) server to a ECommerce SFTP server port 22 (its on PCI domain). The PI server is using Advantco SFTP server to connect to target SFTP server with connection mode as "Permanent" & timeout "300 secs" & Maximum concurrency as "1".
This setup was working fine till 14th April and suddenly we started getting errors in PI server RWB (error details attached - it says "AFW_PROCESS_ERROR"). When we checked with the Ecommerce Admin team who manages the SFTP server, they stated that the PI userid (configured in channel) is creating multiple sessions & keeping them open. At one point we had around 4,200 open sessions but only 40 messages in error in PI. So it is not clear why PI server is creating these many sessions and not closing them. Is it PI server fault ? Or some issue with target SFTP server ?
One important point is the target SFTP server was restarted on 14th due to some issues as the server resources were completely exhausted, at-least that's what was told to PI team, it was just restart with no other changes in SFTP configurations.
We tried setting same connection from our SAP PO (7.31 SP6 Single Stack) server as well using SAP SFTP adapter using same SFTP credentials & Maximum Concurency as "1", timeout "30 Secs" but still SAP PO server is also creating multiple sessions on the target SFTP server.
Due to this the files are not reaching the server and failing in PI / PO only. One thing is in SAP PI we are setting permissions while writing the file as,
* Owner Readable
* Owner Writable
* Group Readable
* Others Readable
While in SAP PO we are setting File permission as "777".
Will there be any relation between setting of these permissions and creation of multiple threads ?
Kindly provide your inputs as soon as possible as the error is in PRODUCTION and its impacting existing business high-time.