I'm trying the hello world script to see if symlinks are working. (Getting a fatal error failed opening required defines.php)...

so my main root is:
/var/www/vhosts/mysite.com/httpdocs

When putting hello.php in the above directory, it states symlinks are not present.

However, when I put the hello world script in /var/www/vhosts/mysite.com/httpdocs/multisites (the multisites subdirectory), then it says that symlinks work. It also says it works in the multisites/slave1 subdirectory

so...I'm not 100% sure how to proceed from here, but the mappings give me 500 server errors like the sym links aren't working...

Here's the result from the primary webstie directory:

(FTP layer is enabled)...

And the result from the slave subdirectory:

I suspect that you are using Plesk environment.

If this is the case, you may encounter problem with Symbolic Link and mainly to use symbolic links with subdomains and domains.

The symbolic link works perfectly inside the current website.

In Plesk, when you want to use Symbolic Link in subdomains and domains, you have to change the default setup of the Plesk configuration for the domains and subdomains.
Plesk explain the the help appendix II how to modify the Plesk configuration with vhost.conf

Contact your server administrator to help you setup your Plesk server and have correct permission when working with subdomains and domains.

Otherwise, you will not be able to share the same joomla installation.

An alternative solution would be to use "parked domain" or "alias domain" to make several domains as synonym and sharing the same joomla installation.
This will not use the Symbolic Link.

Plesk server is not easy to setup.

Yes - I am running plesk...I'm not sure I fully understand what I (or my hosting company) needs to do...

I have the slave site in a subdirectory of the main site (and also have a domain alias setup that points to that directory)...even accessing that folder directly gives me the 500 error

What do I need to do in Plesk or have our site administrator do? Is there a tutorial or something somewhere explaining this in some detail? I'm sure the host will help if I can accurately tell them what I need them to do

Sorry for stupid questions, but just wanting to make sure I know what to do...

Thanks!

(Said differently, if I follow this procedure to setup/modify a vhost.conf file, what needs to be in the vhost.conf file itself?)

The configuration of Plesk is specific to each hosting environment and there is no generic procedure for plesk.

Contact the administrator of your server that should have the skills to setup your server correctly and give you the permission between the domains and subdomains.

The administrator of the server has all the "root" access to analyze the server error log file and identify the reason of the "Internal Server Error" and also the problem relative to the permission.

You probably also encounter a problem related to the "open_basedir" that forbid the access to the directories.

Specifically The errors are as follows:

The plesk error log shows the following entries for the hello.php:
[Thu Oct 27 08:00:14 2011] [error] [client 198.89.160.22] PHP Warning: fopen(/var/www/vhosts/mysite.com/httpdocs/symlink_file4ea955deaa2de.txt) [<a href='function.fopen'>function.fopen</a>]: failed to open stream: Permission denied in /var/www/vhosts/mysite.com/httpdocs/hello.php on line 49



When trying to access the subdomain (mysite.com/multisites/Album_Rock), I get the following in the system error log:
[Thu Oct 27 08:02:18 2011] [error] [client 198.89.160.22] PHP Warning: require_once(/var/www/vhosts/mysite.com/httpdocs/multisites/Album_Rock/includes/defines.php) [<a href='function.require-once'>function.require-once</a>]: failed to open stream: No such file or directory in /var/www/vhosts/mysite.com/httpdocs/multisites/Album_Rock/index.php(11) : eval()'d code on line 19
[Thu Oct 27 08:02:18 2011] [error] [client 198.89.160.22] PHP Fatal error: require_once() [<a href='function.require'>function.require</a>]: Failed opening required '/var/www/vhosts/mysite.com/httpdocs/multisites/Album_Rock/includes/defines.php' (include_path='.:') in /var/www/vhosts/mysite.com/httpdocs/multisites/Album_Rock/index.php(11) : eval()'d code on line 19


The server people have given me full root signon/ssh, so changing things isn't a monumental task (they will do it, too), but I'm not sure what to change. I've changed httpdocs directory to be 757 and 777 from the default 755, but no changes to the above...

There isn't an open basedir error...seems to be an fopen error, which leads me to believe it's a permission issue(?), and the same user has access to the main httpdocs directory and the slave subdirectory (not using a subdomain)...The only difference I notice is it's a different server group for the server root httpdocs (psaserv) vs psacln group for the slave directory and all website content). I got an error when trying to change httpdocs to the psacln group

Any ideas?

First error (hello 49) shows clearly that you are not the owner of the files and folders and that the temporary file can not be created.

The second error also report that you can not open file and this is again probably related to a problem of file and folder ownership.

I suppose that your server does not have the "suPHP" apache module installed that help manage the files and folder ownership correctly.

You probably have different files and folders ownership in your different directories and that you don't have the permission to acces the file and folders.