Neo4j WARNING: Max 1024 open files allowed, minimum of 40 000 recommended. See the Neo4j manual

Question

I installed Neo4j on Ubuntu 12.04 using these instructions: http://www.neo4j.org/download/linux

wget -O - http://debian.neo4j.org/neotechnology.gpg.key | apt-key add -  echo 'deb http://debian.neo4j.org/repo stable/' > /etc/apt/sources.list.d/neo4j.list apt-get update apt-get install neo4j 

I made sure to have the right jdk:

root@precise64:~# java -version java version "1.7.0_45" Java(TM) SE Runtime Environment (build 1.7.0_45-b18) Java HotSpot(TM) 64-Bit Server VM (build 24.45-b08, mixed mode) 

And when I startup neo4j I get this error:

WARNING: Max 1024 open files allowed, minimum of 40 000 recommended. See the Neo4j manual.

So I follow the instructions here: http://docs.neo4j.org/chunked/1.6.2/configuration-linux-notes.html

And add these contents to /etc/security/limits.conf

neo4j   soft    nofile  40000 neo4j   hard    nofile  40000 

And uncomment this line in /etc/pam.d/su

session    required   pam_limits.so 

After I restart the server I validate the new limit

neo4j@precise64:~$ ulimit -n 40000 

Then I restart my server. I still get the same error when starting up.

root@precise64:~# service neo4j-service start WARNING: Max 1024 open files allowed, minimum of 40 000 recommended. See the Neo4j manual. Using additional JVM arguments:  -server -XX:+DisableExplicitGC -Dorg.neo4j.server.properties=conf/neo4j-server.properties -Djava.util.logging.config.file=conf/logging.properties -Dlog4j.configuration=file:conf/log4j.properties -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled Starting Neo4j Server...WARNING: not changing user process [3161]... waiting for server to be ready....... OK. http://localhost:7474/ is ready. 

Even though the service is running as the neo4j user:

root@precise64:~# ps -ef | grep 3161 neo4j     3161     1  2 17:43 pts/0    00:00:10 /usr/bin/java -cp /var/lib/neo4j/lib/concurrentlinkedhashmap-lru-1.3.1.jar:/var/lib/neo4j/lib/geronimo-jta_1.1_spec-1.1.1.jar:/var/lib/neo4j/lib/lucene-core-3.6.2.jar:/var/lib/neo4j/lib/neo4j-cypher-2.0.0.jar:/var/lib/neo4j/lib/neo4j-cypher-commons-2.0.0.jar:/var/lib/neo4j/lib/neo4j-cypher-compiler-1.9-2.0.0.jar:/var/lib/neo4j/lib/neo4j-cypher-compiler-2.0-2.0.0.jar:/var/lib/neo4j/lib/neo4j-graph-algo-2.0.0.jar:/var/lib/neo4j/lib/neo4j-graph-matching-2.0.0.jar:/var/lib/neo4j/lib/neo4j-jmx-2.0.0.jar:/var/lib/neo4j/lib/neo4j-kernel-2.0.0.jar:/var/lib/neo4j/lib/neo4j-lucene-index-2.0.0.jar:/var/lib/neo4j/lib/neo4j-shell-2.0.0.jar:/var/lib/neo4j/lib/neo4j-udc-2.0.0.jar:/var/lib/neo4j/lib/org.apache.servicemix.bundles.jline-0.9.94_1.jar:/var/lib/neo4j/lib/parboiled-core-1.1.6.jar:/var/lib/neo4j/lib/parboiled-scala_2.10-1.1.6.jar:/var/lib/neo4j/lib/scala-library-2.10.3.jar:/var/lib/neo4j/lib/server-api-2.0.0.jar:/var/lib/neo4j/system/lib/asm-3.1.jar:/var/lib/neo4j/system/lib/bcprov-jdk16-140.jar:/var/lib/neo4j/system/lib/commons-beanutils-1.8.0.jar:/var/lib/neo4j/system/lib/commons-beanutils-core-1.8.0.jar:/var/lib/neo4j/system/lib/commons-collections-3.2.1.jar:/var/lib/neo4j/system/lib/commons-compiler-2.6.1.jar:/var/lib/neo4j/system/lib/commons-configuration-1.6.jar:/var/lib/neo4j/system/lib/commons-digester-1.8.1.jar:/var/lib/neo4j/system/lib/commons-io-1.4.jar:/var/lib/neo4j/system/lib/commons-lang-2.4.jar:/var/lib/neo4j/system/lib/commons-logging-1.1.1.jar:/var/lib/neo4j/system/lib/jackson-core-asl-1.9.7.jar:/var/lib/neo4j/system/lib/jackson-jaxrs-1.9.7.jar:/var/lib/neo4j/system/lib/jackson-mapper-asl-1.9.7.jar:/var/lib/neo4j/system/lib/janino-2.6.1.jar:/var/lib/neo4j/system/lib/javax.servlet-3.0.0.v201112011016.jar:/var/lib/neo4j/system/lib/jcl-over-slf4j-1.6.1.jar:/var/lib/neo4j/system/lib/jersey-core-1.9.jar:/var/lib/neo4j/system/lib/jersey-multipart-1.9.jar:/var/lib/neo4j/system/lib/jersey-server-1.9.jar:/var/lib/neo4j/system/lib/jetty-http-9.0.5.v20130815.jar:/var/lib/neo4j/system/lib/jetty-io-9.0.5.v20130815.jar:/var/lib/neo4j/system/lib/jetty-security-9.0.5.v20130815.jar:/var/lib/neo4j/system/lib/jetty-server-9.0.5.v20130815.jar:/var/lib/neo4j/system/lib/jetty-servlet-9.0.5.v20130815.jar:/var/lib/neo4j/system/lib/jetty-util-9.0.5.v20130815.jar:/var/lib/neo4j/system/lib/jetty-webapp-9.0.5.v20130815.jar:/var/lib/neo4j/system/lib/jetty-xml-9.0.5.v20130815.jar:/var/lib/neo4j/system/lib/jsr311-api-1.1.2.r612.jar:/var/lib/neo4j/system/lib/logback-access-1.0.9.jar:/var/lib/neo4j/system/lib/logback-classic-1.0.9.jar:/var/lib/neo4j/system/lib/logback-core-1.0.9.jar:/var/lib/neo4j/system/lib/mimepull-1.6.jar:/var/lib/neo4j/system/lib/neo4j-browser-2.0.0.jar:/var/lib/neo4j/system/lib/neo4j-server-2.0.0-static-web.jar:/var/lib/neo4j/system/lib/neo4j-server-2.0.0.jar:/var/lib/neo4j/system/lib/rhino-1.7R3.jar:/var/lib/neo4j/system/lib/rrd4j-2.0.7.jar:/var/lib/neo4j/system/lib/slf4j-api-1.6.2.jar:/var/lib/neo4j/conf/ -server -XX:+DisableExplicitGC -Dorg.neo4j.server.properties=conf/neo4j-server.properties -Djava.util.logging.config.file=conf/logging.properties -Dlog4j.configuration=file:conf/log4j.properties -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled -Dneo4j.home=/var/lib/neo4j -Dneo4j.instance=/var/lib/neo4j -Dfile.encoding=UTF-8 org.neo4j.server.Bootstrapper root      3238  2056  0 17:49 pts/0    00:00:00 grep --color=auto 3161 

So I think that maybe starting the service as root is the issue, so I shut it down and start it up as the neo4j user.

root@precise64:~# service neo4j-service stop root@precise64:~# su - neo4j  neo4j@precise64:~$ service neo4j-service start Using additional JVM arguments:  -server -XX:+DisableExplicitGC -    Dorg.neo4j.server.properties=conf/neo4j-server.properties -Djava.util.logging.config.file=conf/logging.properties -Dlog4j.configuration=file:conf/log4j.properties -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled Starting Neo4j Server...WARNING: not changing user process [3435]... waiting for server to be ready....... OK. http://localhost:7474/ is ready. cp: cannot create regular file `/var/run/neo4j.pid': Permission denied 

And it fails because the pid file cannot be created. Which I assume means this is not the correct approach, but I go ahead and edit /etc/init.d/neo4j-service to change the location of the pid file to the home folder of the neo4j user:

#PIDFILE=/var/run/$NAME.pid PIDFILE=/var/lib/neo4j/$Name.pid 

And then things startup without error when I run the service as the Neo4j user.

So, my question is: What is the intended behavior? Should starting the service as root work as long as the neo4j user has the correct ulimit permissions, or do I need to modify the startup script/permissions to allow the neo4j user to create it's PID file?

Answer 1

As mentioned in this issue comment and fixed by this commit, since Neo4J 3.1,

you can add a line in /etc/default/neo4j:

NEO4J_ULIMIT_NOFILE=60000 

to set the ulimit setting (60000 open files) for the service.

There is no need anymore to use /etc/security/limits.conf on debian to set the number of open files.

Answer 2

You need to add the following entries into the /etc/security/limits.conf file

root   soft    nofile  40000 root   hard    nofile  40000 

You need to start the service as root or using sudo

When you do that, the user that ends up starting the service is the root user.

If you dont have an entry in the file for the root user, then it would not work.

So, you just need to add those entries in the file and then reboot your server.

I had the same problem and that is how I was able to resolve it.