Important paths on Plesk + centos.

1) Document root for domain.

/var/www/vhosts/domainname/httpdocs

2) path to php.ini

/etc/php.ini 

OR

/usr/local/lib/php.ini

3) maillog path:

/usr/local/psa/var/log/maillog

4) Domain Error log path

/var/www/vhosts/domainname/statistics/logs/error_log

5) 4) Domain access log path

/var/www/vhosts/domainname/statistics/logs/access_log

6) Domain backup path

/var/lib/psa/dumps/domainname

7) Path of the domain email account

/var/qmail/mailnames/domain

8) Check EMails in mail queue :

/var/qmail/bin/qmail-qstat

9) Path to mysql database:

/var/lib/mysql/databasename

10) Plesk named file path

/var/named/run-root/var/domainname

11) The other logs can be found in the below mentioned folder

/var/log/......

12) Document root for domain with ssl.

/var/www/vhosts/domainname/httpsdocs

13) The Redirect conditions can be put in this file.

/var/www/vhosts/domainname/conf/vhost.conf

14) Httpd file for the domain

/var/www/vhosts/domainname/conf/httpd.include

15) cgi-bin path

/var/www/vhosts/domainname/cgi-bin

16) Sub-Domain path

/var/www/vhosts/domainname/subdomains

17) Domain backups

/var/www/vhosts/domainname/library/backups

18) Domain logs

/var/www/vhosts/domainname/library/logs