limits.md

This actually requires https://superuser.com/questions/1200539/cannot-increase-open-file-limit-past-4096-ubuntu/1200818#_=_

Modify **/etc/systemd/user.conf **and /etc/systemd/system.conf with the following line (this takes care of graphical login):

DefaultLimitNOFILE=65535

echo '* hard nofile unlimited' | sudo tee --append /etc/security/limits.conf echo '* soft nofile unlimited' | sudo tee --append /etc/security/limits.conf echo '* soft nproc 32768' | sudo tee --append /etc/security/limits.conf echo '* hard nproc 32768' | sudo tee --append /etc/security/limits.conf echo '* soft memlock unlimited' | sudo tee --append /etc/security/limits.conf echo '* hard memlock unlimited' | sudo tee --append /etc/security/limits.conf

For CentOS / RHEL we need to set nproc limits additionally in 90-nproc.conf

echo '* soft nproc 32768' | sudo tee --append /etc/security/limits.d/90-nproc.conf echo '* hard nproc 32768' | sudo tee --append /etc/security/limits.d/90-nproc.conf

See also http://docs.datastax.com/en/cassandra/2.1/cassandra/install/installRecommendSettings.html

For stuff running with systemd, the settings need to be changed in /etc/systemd/system.conf / /etc/systemd/user.conf:

DefaultLimitNOFILE=infinity
#DefaultLimitNPROC=
DefaultLimitMEMLOCK=infinity

https://unix.stackexchange.com/questions/366352/etc-security-limits-conf-not-applied

There's a bug since Ubuntu 16 apparently.

Basically:

Edit /etc/systemd/user.conf for the soft limit, and add DefaultLimitNOFILE=1048576.
Edit /etc/systemd/system.conf for the soft limit, and add DefaultLimitNOFILE=2097152.