When perfoming an install of Neo4j using the Debian install kit and as detailed at https://neo4j.com/docs/operations-manual/current/deployment/single-instance/debian/, upon completion
you will need to configure the linux configuration option for max files.
If not configured you may encounter errors with a stack trace that includes
java.io.FileNotFoundException: /data/graph.db/schema/label/lucene/_3qn3.fdt (Too many open files) at
or similar.
To configure one needs to create/edit /etc/default/neo4j and define it to include
NEO4J_ULIMIT_NOFILE=40000
Upon start of Neo4j via
service neo4j-service start
the /etc/default/neo4j will be read and the environment variable NEO4J_ULIMIT_NOFILE will then be used in the expression
ulimit -n NEO4J_ULIMIT_NOFILE
and thus set the max open files.
40000 is the recommended number per https://neo4j.com/docs/operations-manual/current/installation/linux/tarball/#linux-open-files
