I am running Ubuntu 12.04 Server, updated, to run a webserver on Tomcat 7.
I have about 1000 clients that are very very often using an RSYNC program to sync files with this server. Those RSyncs are using SSH with a certain user to open connections on the server.
The result is that my server is normally full of connections by the same user. About 5 connections per second at any given time.
Often, when I try to open a regular SSH connection with my Putty client, the connection fails before login with the error, "Server unexpectedly closed network connection". This happens about 6 times for 10 attempts, and for the other 4 attempts, it works normally and I am able to log in as any user.
Is there a overload of connections here?
The server statistics are very calm, saying less then 40% of network usage and less of 2% CPU.
How can I improve this?
I found the solution. There was a limit in terms of connections allowed.
To increase this limit, I simply activated the setting
MaxStartups and set its value to
1000. Now there is no more problem.
I will however check the network and server usage to verify that the traffic is not too much.
Thank you anyway.