Hi,
ok i explain it

was late yesterday ...
1. the problem was that apache uses to much ram, this is a new server xeon 4 core with 4gb
and i am runing just 3 sites with wordpress with ca. 120-200 / Visits / Day for all sites togehter
But apache keeps using more and more ram then i changed php from apache module to cgi and fcgi to test
and it works the ram was on a good level have a look here
But when i use cgi or fcgi my scripts are runing under some other user who has not the sufficent rights to eg write
in folders etc.
i used a little php script to find out under which user the scripts runs
<?php echo(exec("whoami"));?>
when i use php as apache module it runs under "apache" user when i run it under cgi or fcgi it shows nothing
2. so eg. Wordpress the error is that i cant change themes or plugins becouse the script has not the rights to the folders and piwik doesent even start anymore error msg is :
--
Piwik couldn't write to some directories.
Try to Execute the following commands on your server:
chmod 0777 /var/www/vhosts/domain.tld/httpdocs/stat/tmp
chmod 0777 /var/www/vhosts/domain.tld/httpdocs/stat/tmp/templates_c
chmod 0777 /var/www/vhosts/domain.tld/httpdocs/stat/tmp/cache
chmod 0777 /var/www/vhosts/domain.tld/httpdocs/stat/tmp/assets
--
The folders already have 777
3. all the folders on the different webspaces have ether apache or username of the webspace as owner
thanks,
Plesk Version is 10.2 / CentOS 5