Bitbucket Server is not available due to "java.lang.OutOfMemoryError: unable to create new native thread"

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Platform Notice: Server and Data Center Only - This article only applies to Atlassian products on the server and data center platforms.


A short time after starting Bitbucket Server, the application stops without any shutdown request.

The following appears in the catalina.out log:

(info) As of Bitbucket Server 5.x, catalina.out will no longer exist. It will be written to atlassian-bitbucket.log instead.

java.lang.OutOfMemoryError: unable to create new native thread



  • Linux using systemd as the default init system
    • For example, Ubuntu 15.10+ first introduced systemd as the default

Diagnostic Steps

  • No other processes can be started on the server. For example running a ps command returns the following:
atlbitbucket@bitbucket:~$ ps -efH | grep java
-bash: fork: retry: No child processes


The UserTasksMax setting in systemd does not allow the creation of a sufficient number of threads.

This setting has a default of 512.


  1. Increase the value of the DefaultTasksMax setting by changing the relative line in the /etc/systemd/system.conf to provide a higher number (for example 12288):

  2. Restart Bitbucket Server for the change to take effect

Last modified on May 2, 2017

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