sysctl

Add permanent setting

echo "vm.max_map_count=262144" >> /etc/sysctl.d/99-sysctl.conf
sysctl --system
sysctl vm.max_map_count

Set socket maximum connection

/etc/sysctl.conf

net.core.somaxconn=1024

sysctl -p

Set memory overcommit

/etc/sysctl.conf

vm.overcommit_memory = 1

sysctl -p

Change network congestion-control algorithms

When a route has substantial packet loss/congestion/reordering when pushed hard CUBIC could perform very poorly. Switching to BBR could help.

Create a module-load configuration so tcp_bbr is available early at boot:

echo tcp_bbr > /etc/modules-load.d/bbr.conf

Then create:

cat >/etc/sysctl.d/99-bbr.conf <<'EOF'
net.core.default_qdisc=fq
net.ipv4.tcp_congestion_control=bbr
EOF

Apply it:

sysctl --system