netbufmax.sh

#! /bin/bash

# Mike Lloyd, used for increasing ring buffers on CentOS/RHEL. To utilise, just have a local servers.txt file.

clear

echo -e "declaring arrays for in-memory storage."
declare -A {rmem_default,rmem_max,wmem_default,wmem_max,optmem_max}

#rmem defaults.
for i in $(cat servers.txt); do
	rmem_default[$(echo "$i")]=$(ssh root@$i "cat /proc/sys/net/core/rmem_default")
	done

echo -e "\nserver ring memory defaults."
tput sgr0
for i in "${!rmem_default[@]}"; do 
	echo "server: $i"
	echo "ring default: ${rmem_default[$i]}"
done

#rmem maxs
for i in $(cat servers.txt); do
	rmem_max[$(echo "$i")]=$(ssh root@$i "cat /proc/sys/net/core/rmem_max")
	done

echo -e "\nserver ring memory maximums."
for i in "${!rmem_max[@]}"; do 
	echo "server: $i"
	echo "ring max: ${rmem_max[$i]}"
done

#wmem defaults.
for i in $(cat servers.txt); do
	wmem_default[$(echo "$i")]=$(ssh root@$i "cat /proc/sys/net/core/wmem_default")
	done

echo -e "\nserver default send buffer size."
for i in "${!wmem_default[@]}"; do 
	echo "server: $i"
	echo "send default: ${wmem_default[$i]}"
done

#mem maxes
for i in $(cat servers.txt); do
	wmem_max[$(echo "$i")]=$(ssh root@$i "cat /proc/sys/net/core/wmem_max")
	done

echo -e "\nserver max send buffer size."
for i in "${!wmem_max[@]}"; do 
	echo "server: $i"
	echo "send max: ${wmem_max[$i]}"
done

#socket details
for i in $(cat servers.txt); do
	optmem_max[$(echo "$i")]=$(ssh root@$i "cat /proc/sys/net/core/optmem_max")
	done

echo -e "\nserver option memory buffer size."
for i in "${!optmem_max[@]}"; do 
	echo "server: $i"
	echo "send max: ${optmem_max[$i]}"
done

echo -e "\n\n\nYou have 30 seconds to review the material to verify changes. Press CTRL+C to cancel.\n\n\n"
sleep 30

for i in "${!rmem_max[@]}"; do
	echo -e "\nchanging server $i to maximum ring buffer size."
 	ssh root@$i "sysctl -w net.core.rmem_max=${rmem_max[$i]}"
done

for i in "${!wmem_max[@]}"; do
	echo -e "\nchanging server $i to maximum send buffer size."
 	ssh root@$i "sysctl -w net.core.wmem_max=${wmem_max[$i]}"
done

for i in $(cat servers.txt); do
	echo -e "\nflushing route for server $i."
	ssh root@$i "sysctl -w net.ipv4.route.flush=1"
# 
	echo -e "restarting sysctl without reboot on server $i."
	ssh root@$i "sysctl -p"
done

echo -e "\nremoving arrays."
unset {rmem_default,rmem_max,wmem_default,wmem_max,optmem_max}

echo -e "verifying new settings."

for i in $(cat servers.txt); do
 	echo -e "\nserver $i networking:"
 	ssh root@$i "grep net /etc/sysctl.conf"
done

exit 0