### remove redis Warnings about

# WARNING: The TCP backlog setting of 511 cannot be enforced because
#  /proc/sys/net/core/somaxconn is set to the lower value of 128.
net.core.somaxconn=512

# WARNING overcommit_memory is set to 0! Background save may fail
# under low memory condition. To fix this issue add
# 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or
# run the command 'sysctl -w vm.overcommit_memory=1' for this to take
# effect.
vm.overcommit_memory=1