Tech Tip: Send an Email Alert When Your Disk Space Gets Low
October 13th, 2009 by Mallik Arjun in
If you don't want to step up to a full monitoring solution such as Nagios you can create your own scripts for monitoring the things that you want to monitor, such as disk space. The following script alerts you when your root partition is almost full:
#!/bin/bash
CURRENT=$(df / | grep / | awk '{ print $5}' | sed 's/%//g')
THRESHOLD=90
if [ "$CURRENT" -gt "$THRESHOLD" ] ; then
mail -s 'Disk Space Alert' mailid@domainname.com << EOF
Your root partition remaining free space is critically low. Used: $CURRENT%
EOF
fi
The script sends an email when the disk usage rises above the percentage specified by the THRESHOLD varialbe (90% here).
To run it daily, for example, save the script to the file sample.sh in your home directory, change the email to your email, and add the following line at the end of /etc/crontab file:
@daily ~/sample.sh__________________________
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There are some similar scripts available
On October 28th, 2009 Anonymous (not verified) says:
It's a very basic topic for linux administration. There are some similar scripts available at Admon.org, this site is dedicated for system monitoring and administration.
There are some problems with
On October 22nd, 2009 T-One (not verified) says:
There are some problems with filesystems like cdrom drives, proc and stuff like that, so it would be better to filter that stuff, thats the script i use:
ADMIN="yourmail@example.com" # set alert-level 90 % standard ALERT=10 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 [ $usep -ge $ALERT ]; then echo "space low on \"$partition ($usep%)\", on server $(hostname) at $(date)" | mail -s "Alert: Free space low, $usep % used on $partition" $ADMIN fi doneIs it possible to set the
On October 21st, 2009 Supernoob (not verified) says:
Is it possible to set the execution of the script at a specific hour of the day?
Thanx
Yes, see these
On October 21st, 2009 Mitch Frazier says:
Check these: cron video and cron article.
__________________________Mitch Frazier is an Associate Editor for Linux Journal and the Web Editor for linuxjournal.com.
Fixed
On October 14th, 2009 CyberCowboy (not verified) says:
on Ubuntu Karmic the 2nd line needs to read like this
CURRENT=$(df / | grep / | awk '{ print $4}' | sed 's/%//g')
Note the change from 5 to 4 in the awk portion of the line.
Perhaps check all
On October 13th, 2009 David Tangye (not verified) says:
Perhaps check all automounted filesystems ?
for vFS in `awk '!/^#/{if ($6 > 0) print $2}' /etc/fstab` do df $vFS | \ awk -v THRESHOLD=90 ' !/^Filesystem/{ VUSE=substr($5,1,length($5)-1) if (VUSE >= THRESHOLD) {print VUSE " " $6}}' done | \ mail -e -s 'Disk Space Alert' mailid@domainname.comHere you do not need grep and sed
On October 13th, 2009 Andreas Schamanek (not verified) says:
If you use _awk_ you can make it also do what _grep_ and _sed_ do. An easy way is
CURRENT=$(df / | awk '/\// { print strtonum($5)}')More correct would be
CURRENT=$(df / | awk '/\// { sub(/%$/,"",$5); print $5}')But even cooler is the combination of df, awk and mail to get an alert for any file system above THRESHOLD:
df | awk "{ df=strtonum(\$5); if (df > $THRESHOLD) print; }" \ mail -e -s 'Disk Space Alert' mailid@domainname.comThis basically all that is needed. _mail -e_ does not send a mail if the body is empty, i.e. when no file system is above THRESHOLD.
HTH.
total noob question
On October 13th, 2009 Anonymous (not verified) says:
That's great, but how do I set things up so I can email from the command line?
> set things up so I can email from the command line
On October 14th, 2009 lefty.crupps (not verified) says:
You need to install a package which contains the 'mail' executable ('mail' program). On most systems that I've dealt with, this 'mail' command comes with the base install or comes as a part of an email transport system, such as Exim4 or Sendmail.
Try running this; the [Ctrl][D] key-combo tells the app when you're done composing:
If you have long device
On October 13th, 2009 Anonymous (not verified) says:
If you have long device names like:
/dev/mapper/VolGroup00-LogVol00
you have to use:
df -P (for POSIX output)
to ensure one line per device output.
Otherwise your example does not work in every situation.
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