kvm swap file

autoswap.sh

#!/bin/bash
######################################
# auto swap creator for centminmod.com
######################################
# calculation based on largest free disk
# space based partition size
LARGESTPART=$(df -k -x tmpfs -x devtmpfs -l -P | awk 'NR>=2 {print $4,$6}' | sort -k1 -nr | head -n1)
LPARTSIZE=$(echo $LARGESTPART | awk '{print $1}')
LPARTNAME=$(echo $LARGESTPART | awk '{print $2}')
SWAPBASEDIR="$LPARTNAME"
#####################################
# check to see if partition name ends with / otherwise
# added ending forward slash /
if [[ -z "$(echo $SWAPBASEDIR | grep '\/$')" ]]; then
  SWAPBASEDIR="${LPARTNAME}/"
fi
#####################################
echo $LARGESTPART
echo $LPARTSIZE
echo $LPARTNAME
#####################################

if [[ "$(echo $LPARTSIZE | bc)" -ge '13631488' ]]; then
  # 2GB Swap when greater than 13631488 bytes free disk space
  SWAPSIZE='2048k'
elif [[ "$(echo $LPARTSIZE | bc)" -ge '10485760' ]] && [[ "$(echo $LPARTSIZE | bc)" -lt '13631488' ]]; then
  # 1GB Swap when between >10485760 and <13631488 bytes free disk space
  SWAPSIZE='1024k'
elif [[ "$(echo $LPARTSIZE | bc)" -ge '9961000' ]] && [[ "$(echo $LPARTSIZE | bc)" -lt '10485760' ]]; then
  # 512MB Swap when between >9961000 and <10485760 bytes free disk space
  SWAPSIZE='512k'
elif [[ "$(echo $LPARTSIZE | bc)" -ge '9437184' ]] && [[ "$(echo $LPARTSIZE | bc)" -lt '9961000' ]]; then
  # 256MB Swap when between >9437184 and <9961000 bytes free disk space
  SWAPSIZE='256k'
fi

# create swap file if one doesn't exist and if system is a
# non-OpenVZ system
if [[ -z "$(swapon -s)" ]] && [[ ! -f /proc/user_beancounters ]]; then
  echo "create $SWAPSIZE swap file"
  dd if=/dev/zero of=${SWAPBASEDIR}swapfile bs=1024 count=$SWAPSIZE
  ls -lah ${SWAPBASEDIR}swapfile
  mkswap ${SWAPBASEDIR}swapfile
  swapon ${SWAPBASEDIR}swapfile
  chown root:root ${SWAPBASEDIR}swapfile
  chmod 0600 ${SWAPBASEDIR}swapfile
  swapon -s
  echo "${SWAPBASEDIR}swapfile swap swap defaults 0 0" >> /etc/fstab
  mount -a
fi

gistfile1.txt

df -k
Filesystem        1K-blocks    Used Available Use% Mounted on
/dev/ploop63399p1  25798972 3761296  20727164  16% /
devtmpfs             524288       0    524288   0% /dev
tmpfs                524288       0    524288   0% /dev/shm
tmpfs                524288     164    524124   1% /run
tmpfs                524288       0    524288   0% /sys/fs/cgroup

find non-tmpfs or non-devtmpfs based block device/partitions and print from row 2 or higher

df -k -x tmpfs -x devtmpfs -l | awk 'NR>=2 {print $4,$6}'

20727176 /

sorting by column 1

df -k -l | awk 'NR>=2 {print $4,$6}' | sort -k1

20727176 /
524124 /run
524288 /dev
524288 /dev/shm
524288 /sys/fs/cgroup

swap.sh

#!/bin/bash

echo "create 2GB swap file"
dd if=/dev/zero of=/swapfile bs=1024 count=2048k
ls -lah /swapfile
mkswap /swapfile
swapon /swapfile
chown root:root /swapfile
chmod 0600 /swapfile
swapon -s
echo "/swapfile swap swap defaults 0 0" >> /etc/fstab
mount -a