I am trying to load-test my WP blog (just to see...), using loadimpact.com .But the error log fills up with errors like this:
Can I change this limit of 30 ?
Not without very good reason. That limit is pretty much impossible to hit in ordinary use.
If my understanding is correct: this limit is applied to each IP? So if 100 different users came from 100 different IPs (using default concurrency settings on their browsers), this limit would not be hit?
Correct. This limit is on the number of connections which a single IP can make.
If you are on a Shared Hosting platform, you will find 4 variables in the following file that begin with 'Max', and which control the limits of ssh/ftp/sftp connections:
That file only has to do with FTP connections. (Hence the "ftp" in "proftpd".) It has no effect on ssh, nor on the web server.
ok... my bad... curious, searching /etc/ssh/sshd_config on shared and ps, but don't see explicit vars set there for connection limits. Is it a secret where it is set, and are there other limiting ssh vars that are similar to the ftp ones, that would be good to know about?
There are some limits on the number of processes one user can have running at a time, which will end up limiting the number of SSH connections you can have active. Like all the other limits being discussed here, though, it is not a limit you will ever run into in ordinary usage (it's somewhere around 10 or 20, I think).