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I'm running an Ubuntu 17.10 server on the VDS. I'm running a 3proxy on it.
The problem is that VDS somehow does not allow running more than 5000 threads per process, as I think. I think so because the 3proxy process never exceed 5000 threads.

EDIT: the error I see in the logs is:

pthread_create():_Resource_temporarily_unavailable

So I want to check if I am right about it by checking the real thread-per-process limit. My idea is to create a script, which will start as many threads as system will allow, and check the result of how many will it be.

And my problem is that I don't know how to create such a script

Vladyslav Matviienko
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  • Please see [here](https://askubuntu.com/questions/845380/bash-fork-retry-resource-temporarily-unavailable) and [here](https://askubuntu.com/questions/882624/max-number-of-simaltenous-running-process). I was able to get to 118000 threads. – Doug Smythies Feb 15 '18 at 14:33

1 Answers1

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There is no threads per process limit!

But there is a limit on the total number of processes on the system (threads are essentially just processes with a shared address space on Linux)

cat /proc/sys/kernel/threads-max

The default is the number of memory pages divided by 4. You can increase this like:

echo 100000 > /proc/sys/kernel/threads-max

There is also a limit of processes (threads) that a single user may create, see ulimit for this, but this should be unlimited on Ubuntu.

Robert Riedl
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  • I have tried that already, as well as playing with ulimit setting large values. I forgot to mention the erro message I get: `pthread_create():_Resource_temporarily_unavailable` – Vladyslav Matviienko Feb 15 '18 at 08:30
  • What is the output of `cat /proc/sys/kernel/threads-max` ? – Robert Riedl Feb 15 '18 at 08:32
  • also `echo 100000 > /proc/sys/kernel/threads-max` doesn't change `proc/sys/kernel/threads-max`, if I check it after I run the command, it is the same as before: 63814 – Vladyslav Matviienko Feb 15 '18 at 08:32
  • so this is not a system limit but rather a limit of your software, 3proxy – Robert Riedl Feb 15 '18 at 08:35
  • As for actual process limit: I have a bash script, which starts 20000 `sleep 20 &` commands, and as for `top` maximum `Tasks: 10980 total`, and I'm getting `fork: retry: Resource temporarily unavailable` after it reaches 10980 – Vladyslav Matviienko Feb 15 '18 at 08:36
  • looking at some documentation it says `A number of simulatineous connections per service is limited by 'maxconn' option. Default maxconn value since 3proxy 0.8 is 500.` and `ou may want to set 'maxconn' to higher value. Under this configuration: maxconn 1000` – Robert Riedl Feb 15 '18 at 08:36
  • `limit of your software` I thought same way until I got another server, on which it is able to start 18000 threads just fine with same config. Config `maxconn` is 100000 – Vladyslav Matviienko Feb 15 '18 at 08:37
  • Let us [continue this discussion in chat](http://chat.stackexchange.com/rooms/73178/discussion-between-robert-riedl-and-metalurgus). – Robert Riedl Feb 15 '18 at 08:37