Fix method to retrieve and compute real used pages (used - free pages)

README.md

@@ -3,7 +3,24 @@ Icinga/Nagios plugin to check MDB database
 
 This script could be used as Icinga/Nagios check plugin to check MDB database.
 
-This script use _mdb_stat_ utility to do this check.
+This script use *mdb_stat* utility to do this check.
+
+**Note :** *mdb_stat* is not available on Debian Wheezy but it could be backport from Jessie.
+
+Installation
+------------
+
+```
+apt-get -y install lmdb-utils bc
+git clone https://gogs.zionetrix.net/bn8/check_mdb.git /usr/local/src/check_mdb
+mkdir -p /usr/local/lib/nagios/plugins
+ln -s /usr/local/src/check_mdb/check_mdb /usr/local/lib/nagios/plugins/
+echo "nagios ALL=NOPASSWD: /usr/local/lib/nagios/plugins/check_mdb" > /etc/sudoers.d/nagios-slapd-mdb
+chmod 0400 /etc/sudoers.d/nagios-slapd-mdb
+echo "command[check_mdb]=sudo /usr/local/lib/nagios/plugins/check_mdb" > /etc/nagios/nrpe.d/ldap-mdb.cfg
+service nagios-nrpe-server reload
+```
+
 
 Usage
 -----

check_mdb

@@ -90,7 +90,7 @@ do
 	esac
 done
 
-CMD="$MDB_STAT -e $DB_PATH"
+CMD="$MDB_STAT -ef $DB_PATH"
 debug "mdb_stat command = '$CMD'"
 
 if [ -n "$SUDO_USER" ]
@@ -111,8 +111,12 @@ then
 	exit 3
 fi
 
+raw_used_pages=$( echo -e "$OUTPUT"|grep -E '^ +Number of pages used: '|sed 's/^ \+Number of pages used: \([0-9]\+\)$/\1/' )
+free_pages=$( echo -e "$OUTPUT"|grep -E '^ +Free pages: '|sed 's/^ \+Free pages: \([0-9]\+\)$/\1/' )
+let used_pages=raw_used_pages-free_pages
+debug "Used/free pages: $raw_used_pages / $free_pages. Real used pages: $used_pages"
+
 max_pages=$( echo -e "$OUTPUT"|grep -E '^ +Max pages: '|sed 's/^ \+Max pages: \([0-9]\+\)$/\1/' )
-used_pages=$( echo -e "$OUTPUT"|grep -E '^ +Number of pages used: '|sed 's/^ \+Number of pages used: \([0-9]\+\)$/\1/' )
 let perc_used=$used_pages*100/$max_pages
 debug "Used/max pages: $used_pages / $max_pages ($perc_used%)"