1. delete unused domains
A good start is to go through apache2 config:

   grep ^Use domains.conf |cut -f4 -d\ |sort >/tmp/d.txt
   
for a small number of domains, it is pretty quick and 100% correct going through the list manualy
<code bash>
   domains=`grep ^Use domains.conf |cut -f4 -d\ | xargs`
   for i in $domains; do
      host $d
      read yn
      if [ "${yn}foo" != 'nfoo' ]; then
          echo $d >>/tmp/ws2.alive
      fi
   done
</code>

Or automaticaly:
<code bash>
for i in `cat /tmp/d.txt|xargs`; do
 host $i 8.8.8.8 |grep 146.255 -q || echo $i >>/tmp/dead.tmp;
done
sort /tmp/dead.tmp >/tmp/deads.txt
</code>
    diff -u /tmp/ds.txt /tmp/dead2.txt |sed -n 's/^-\(.*\)/\1/p' >/tmp/alive.txt

Generate the domains again
   diff -u /tmp/ws2.alive /tmp/ws.dead | sed -n 's/^-\(.\)\(.*\)/Use VhostCGI \1 \1\2/p'

Save this list for later editing the DNS.


2. remove dead databases
<code bash>
cat /tmp/ws2.alive |tr -s . _ |sort >/tmp/db.alive
ls -1 /var/lib/mysql/ > /tmp/db.old
domains =`diff -u db.old db.alive | grep ^-|tr -s _ .|cut -f2 -d-`

for i in $domains; do host $i|grep 146.255.31.12 -q && echo $i; done >> /tmp/db.alive
   sort db.alive >db2.alive
These are dead 

   diff -u db.old db2.alive | sed -n 's/^-\(.*\)/drop database \1;/p'
</code>

Change DNS
a) those who has dns at us
<code bash>
   cd /mnt/swraid/conf/bind/domains_master
   sed -i 's/146.255.31.12/167.233.3.19/' *
</code>
b) the rest - contact by email