What is the best practice in using FTP adapter which is in vendor network ( external) ? If the connection parameter is set as permanent, or file per transfer, whats the major difference in performance and security? The vendor FTP has uname and pwd for each interfaces from SAP system. If I use file per transfer, everytime the data is sent, FTP takes it in a directory using uname and pwd access. Will it affect the performance ?
Permanently should be used when the FTP service is stable and will not go down at all. If the FTP server goes down then if your File Adapter is in permanent mode it will error out due to connectivity issues. You will have to manually restart the file adapter for the connectivity to happen again.
Per file transfer is used when a permamanent connection cannot be guaranteed. Evey polling interval the file adapter will connetc to the FTP service, transfer the file and then close the connection.
There will be a slight performance overhead in per file transfer but I dont think this will be significant and should be negligble.