How to check swap space in linux and system’s paging

# PLATFORM: AIX, Solaris, HP-UX and Linux Only
#
# PURPOSE: This shell script is used to produce a report of
# the system’s paging or swap space statistics including:
#
# Total paging space in MB, MB of Free paging space,
# MB of Used paging space, % of paging space Used, and
# % of paging space Free
#
# set -x # Uncomment to debug this shell script
# set -n # Uncomment to check command syntax without any execution
#
###########################################################
################ DEFINE VARIABLES HERE ####################
PC_LIMIT=65 # Upper limit of Swap space percentage
# before notification
THISHOST=$(hostname) # Host name of this machine
###########################################################
################ INITIALIZE THE REPORT ####################
echo “Swap Space Report for $THISHOST\n”
date
###########################################################
################ DEFINE FUNCTIONS HERE ####################
function SUN_swap_mon
{
############# CAPTURE AND PROCESS THE DATA ################
# Use two awk statements to extract the $9 and $11 fields
# from the swap -s command output
SW_USED=$(swap -s | awk ‘{print $9}’ | cut -dk -f1)
SW_FREE=$(swap -s | awk ‘{print $11}’ | cut -dk -f1)
# Add SW_USED to SW_FREE to get the total swap space ((SW_TOTAL = SW_USED + SW_FREE))

# Calculate the percent used and percent free using the
# bc utility in a here documentation with command substitution
PERCENT_USED=$(bc <<EOF
scale=4
($SW_USED / $SW_TOTAL) * 100
EOF
)
PERCENT_FREE=$(bc <<EOF
scale=4
($SW_FREE / $SW_TOTAL) * 100
EOF
)
# Convert the KB measurements to MB measurements
((SW_TOTAL_MB = SW_TOTAL / 1000))
((SW_USED_MB = SW_USED / 1000))
((SW_FREE_MB = SW_FREE / 1000))
# Produce the remaining part of the report
echo “Total Amount of Swap Space:${SW_TOTAL_MB}MB”
echo “Total KB of Swap Space Used:${SW_USED_MB}MB”
echo “Total KB of Swap Space Free:${SW_FREE_MB}MB”
echo “Percent of Swap Space Used:${PERCENT_USED}%”
echo “Percent of Swap Space Free:${PERCENT_FREE}%”
# Grab the integer portion of the percent used
INT_PERCENT_USED=$(echo $PERCENT_USED | cut -d. -f1)
# Check to see if the percentage used maximum threshold
# has been exceeded
if (( PC_LIMIT <= INT_PERCENT_USED ))
then
# Percent used has exceeded the threshold, send notification
tput smso # Turn on reverse video!
echo “\n\nWARNING: Swap Space has Exceeded the ${PC_LIMIT}% Upper
Limit!\n”
tput rmso # Turn off reverse video!
fi

echo “\n”
}
###########################################################
function Linux_swap_mon
{
free -m | grep -i swap | while read junk SW_TOTAL SW_USED SW_FREE
do
# Use the bc utility in a here document to calculate
# the percentage of free and used swap space.
PERCENT_USED=$(bc <<EOF
scale=4
($SW_USED / $SW_TOTAL) * 100
EOF
)
PERCENT_FREE=$(bc <<EOF
scale=4
($SW_FREE / $SW_TOTAL) * 100
EOF
)
# Produce the rest of the paging space report:
echo “Total Amount of Swap Space:${SW_TOTAL}MB”
echo “Total KB of Swap Space Used:${SW_USED}MB”
echo “Total KB of Swap Space Free:${SW_FREE}MB”
echo “Percent of Swap Space Used:${PERCENT_USED}%”
echo “Percent of Swap Space Free:${PERCENT_FREE}%”
# Grab the integer portion of the percent used to
# test for the over limit threshold
INT_PERCENT_USED=$(echo $PERCENT_USED | cut -d. -f1)
if (( PC_LIMIT <= INT_PERCENT_USED ))
then
tput smso
echo “\n\nWARNING: Paging Space has Exceeded the \
${PC_LIMIT}% Upper Limit!\n”
tput rmso

fi
done
echo “\n”
}
###########################################################
function HP_UX_swap_mon
{
# Start a while read loop by using the piped in input from
# the swapinfo -tm command output.
swapinfo -tm | grep dev | while read junk SW_TOTAL SW_USED \
SW_FREE PERCENT_USED junk2
do
# Calculate the percentage of free swap space
((PERCENT_FREE = 100 – $(echo $PERCENT_USED | cut -d% -f1) ))
echo “Total Amount of Swap Space:${SW_TOTAL}MB”
echo “Total MB of Swap Space Used:${SW_USED}MB”
echo “Total MB of Swap Space Free:${SW_FREE}MB”
echo “Percent of Swap Space Used:${PERCENT_USED}”
echo “Percent of Swap Space Free:${PERCENT_FREE}%”
# Check for paging space exceeded the predefined limit
if (( PC_LIMIT <= $(echo $PERCENT_USED | cut -d% -f1) ))
then
# Swap space is over the predefined limit, send notification
tput smso # Turn on reverse video!
echo “\n\nWARNING: Swap Space has Exceeded the\
${PC_LIMIT}% Upper Limit!\n”
tput rmso # Turn reverse video off!
fi
done
echo “\n”
}

###########################################################
function AIX_paging_mon
{
################ DEFINE VARIABLES HERE ####################
PAGING_STAT=/tmp/paging_stat.out # Paging Stat hold file
############# CAPTURE AND PROCESS THE DATA ################
# Load the data in a file without the column headings
lsps -s | tail +2 > $PAGING_STAT
# Start a while loop and feed the loop from the bottom using
# the $PAGING_STAT file as redirected input
while read TOTAL PERCENT
do
# Clean up the data by removing the suffixes
PAGING_MB=$(echo $TOTAL | cut -d ‘MB’ -f1)
PAGING_PC=$(echo $PERCENT | cut -d% -f1)
# Calculate the missing data: %Free, MB used and MB free
(( PAGING_PC_FREE = 100 – PAGING_PC ))
(( MB_USED = PAGING_MB * PAGING_PC / 100 ))
(( MB_FREE = PAGING_MB – MB_USED ))
# Produce the rest of the paging space report:
echo “Total MB of Paging Space:$TOTAL”
echo “Total MB of Paging Space Used:${MB_USED}MB”
echo “Total MB of Paging Space Free:${MB_FREE}MB”
echo “Percent of Paging Space Used:${PERCENT}”
echo “Percent of Paging Space Free:${PAGING_PC_FREE}%”
# Check for paging space exceeded the predefined limit
if ((PC_LIMIT <= PAGING_PC))
then
# Paging space is over the limit, send notification
tput smso # Turn on reverse video!
echo “\n\nWARNING: Paging Space has Exceeded the ${PC_LIMIT}%
\
Upper Limit!\n”
tput rmso # Turn off reverse video

fi
done < $PAGING_STAT
rm -f $PAGING_STAT
# Add an extra new line to the output
#echo “\n”
}
###########################################################
################## BEGINNING OF MAIN ######################
###########################################################
# Find the Operating System and execute the correct function
case $(uname) in
AIX) AIX_paging_mon
;;
HP-UX) HP_UX_swap_mon
;;
Linux) Linux_swap_mon
;;
SunOS) SUN_swap_mon
;;
*) echo “\nERROR: Unsupported Operating System…EXITING…\n”
exit 1
;;
esac

Example Output:

“Swap Space Report for localhost.localdomainn”
Sun Jul 15 04:58:13 IST 2012
“Total Amount of Swap Space:3519MB”
“Total KB of Swap Space Used:0MB”
“Total KB of Swap Space Free:3519MB”
“Percent of Swap Space Used:0%”
“Percent of Swap Space Free:100.0000%”

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