source: npl/commonservers/mysql_conf/root/service/mysql/run

#!/bin/sh
if [ -e /etc/my.init ];  then
    INIT="--init-file=/etc/my.init"
fi

export TMPDIR=/home/system/tmp

### dynamicly configure bufferpool
#max size of total mysqld=4Gb on 32 bits systems, but there is other stuff in mysqld that uses memory as well. 2200000k seems the maximum for our config on 32 bit
MAX_POOL=1800000 

#total system mem in KB
MEM_KB=`cat /proc/meminfo | grep MemTotal | sed 's/[^0-9]//g'`

#manual says: pool size 50% of memory, but we use 25% (zarafa also needs a lot)
(( MEM_POOL = MEM_KB / 4 ))
if [ "$MEM_POOL" -ge $MAX_POOL ]; then
        MEM_POOL=$MAX_POOL
fi

#make the config update atomic. (it happend more then once that during a crash/reset the config file ended up zero bytes )
cat /etc/my.cnf | sed "s/^innodb_buffer_pool_size.*/innodb_buffer_pool_size = "$MEM_POOL"K/g" > /etc/my.cnf.tmp
sync
mv /etc/my.cnf.tmp /etc/my.cnf

cd /
umask 077
exec mysqld --basedir=/usr --datadir=/home/system/mysql5 --user=mysql --log-error=/home/system/mysql5/mysql.err --pid-file=/home/system/mysql5/mysql.pid --socket=/var/run/mysql/mysql.sock --port=3306 $INIT