Script to Watch Disk Space
Watch Disk Space using Bash Script
Some time Space issue cause to crash or hang our server which makes loss of our data which comes from web users. So there is need to monitor disk space which would automatically send mail to us if it reaches some critical values so that we can delete some old or unusable data from server and free some space.
df displays the amount of disk space available on the file system containing each file name argument. If no file name is given, the space available on all currently mounted file systems is shown. Read man page of df if you are new to df command.
Steps to monitor disk space and report us
=> Find disk space using df for each drive
=> Filter out filesystem and find out the percentage of space using grep
=> Write a shell script and send mail to us
Step # 1: First get disk space using df command
$ df -H
Output:
Filesystem Size Used Avail Use% Mounted on /dev/hdb1 20G 14G 5.5G 71% / tmpfs 394M 4.1k 394M 1% /dev/shm /dev/hdb5 29G 27G 654M 98% /nas/www
Step # 2: Next filter out filesystem and find out the percentage of space
df -H | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{ print $5 " " $6 }'
Output:
51% / 21% /boot 96% /media/Materials
Step # 3: Write a shell script
Above command displays field 5 and 1 of df command. Now all you need to do is write a script to see if the percentage of space is >= 90% (download script):
#!/bin/sh
df -H | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{ print $5 " " $6 }' | while read output;
do
usep=$(echo $output | awk '{ print $1}' | cut -d'%' -f1 )
partition=$(echo $output | awk '{ print $2 }' )
if echo $usep | egrep -q '^[0-9]+$'; then
if [ $usep -ge 90 ]; then
echo "Running out of space \"$partition ($usep%)\" on $(hostname) as on $(date)" |
mail -s "Alert: Almost out of disk space $usep%" [email protected]
fi
fi
done
Setup Cron job
Save and install script as crontab.
install as cronjob
crontab -e
Write cronjob as per your requirement
0 1 * * * /path/to/scriptalert
