Set Ubuntu 20.04 mongodb recommended ulimits

ulimits_ubuntu_mongodb.sh

# ulimit -a
# sudo sysctl net.ipv4.tcp_fastopen=3
# sudo sysctl vm.max_map_count=524288 

#  note: "-l" (max locked memory) has no soft limit 
#  apt-get install numactl

sudo sh -c "sysctl -w net.ipv4.tcp_fastopen=3 ; \
 sysctl -w vm.max_map_count=524288 ; \
 ulimit -l unlimited ; \
 ulimit -S -v unlimited ; \
 sudo -u ubuntu /bin/bash -c '\
 ulimit -S -f unlimited; \
 ulimit -S -t unlimited; \
 ulimit -S -n 64000; \
 ulimit -S -m 65536; \
 numactl --interleave=all ./bin/mongod \
  --replSet rs0 --dbpath ./dbfiles \
  --bind_ip 0.0.0.0 \
  -port 27017 \
  --logpath ./dblogs/mongod.log 2>&1 &'"
  
  sleep 5 && echo "rs.initiate()" | mongosh