Sometimes it is completing the 40 MB file transfer less than a minute. But sometimes it is taking couple of minutes to complete.
Our observation. When we see the below message "Increasing the send buffer value from current value to double, it will transfer the file less than a minute.
When no change in Increasing send buffer value . It is taking long time to transfer the files.
Please suggest us do we have any parameters to change in WINSCP/SFTP client.
Please find below log for reference.
• Tried to compare SFTP logs for good performance (26 secs) vs. poor performance (12 mins 30 secs). In both the cases file size remains same.
• During slow performance, I don’t see Increasing send buffer entries and ~7 mins between below two events (in attached file, refer log events between 2021-03-03 02:41:04.955 and 2021-03-03 02:53:30.483)
o Initially buffer size is set to 262144 and later it’s not increasing
. 2021-03-03 02:41:04.955 Send buffer: 262144 > 2021-03-03 02:41:07.784 Type: SSH_FXP_WRITE, Size: 32761, Number: 1798 . 2021-03-03 02:47:46.698 2560 skipped SSH_FXP_WRITE, SSH_FXP_READ, SSH_FXP_DATA and SSH_FXP_STATUS packets.
o Initially buffer size is set to 262144
. 2021-03-03 03:39:07.966 Send buffer: 262144
> 2021-03-03 03:39:10.388 Type: SSH_FXP_WRITE, Size: 32761, Number: 1798 . 2021-03-03 03:39:11.325 Increasing send buffer from 262144 to 524288 . 2021-03-03 03:39:12.325 Increasing send buffer from 524288 to 1048576 . 2021-03-03 03:39:13.326 Increasing send buffer from 1048576 to 2097152 . 2021-03-03 03:39:18.827 2509 skipped SSH_FXP_WRITE, SSH_FXP_READ, SSH_FXP_DATA and SSH_FXP_STATUS packets.