I have several domains working flawlessly with Apache. Today I tried adding a subdomain to one of them and that caused the problem.

In /etc/apache2/sites-available/ I have "domain.com" which works fine. I then duplicated it and renamed to "sub.domain.com" and ln -s'd it to sites-enabled.

When I tried to start Apache it failed. The subdomain is already added in /etc/hosts as "sub.domain.com". What might be causing this, any ideas?

"domain.com" in sites-available:

<VirtualHost *>
ServerAdmin admin@domain.com
ServerName domain.com
ServerAlias www.domain.com

DocumentRoot /var/www/vhosts/domain.com/htdocs

#<Directory /var/www/vhosts/domain.com>
AddHandler fcgid-script .php
FCGIWrapper /usr/lib/cgi-bin/php5 .php
#</Directory>

LogLevel warn
ErrorLog /var/www/vhosts/domain.com/log/error.log
CustomLog /var/www/vhosts/domain.com/log/access.log combined

</VirtualHost>

... and "sub.domain.com" file:

<VirtualHost *>
ServerAdmin admin@domain.com
ServerName sub.domain.com

DocumentRoot /var/www/vhosts/domain.com/subdomains/sub/htdocs

#<Directory /var/www/vhosts/domain.com/subdomains/sub>
#AddHandler fcgid-script .php
#FCGIWrapper /usr/lib/cgi-bin/php5 .php
#</Directory>

LogLevel warn
ErrorLog /var/www/vhosts/domain.com/subdomains/sub/log/error.log
CustomLog /var/www/vhosts/domain.com/subdomains/sub/log/access.log combined

</VirtualHost>

The most common cause I've had for Apache not starting up is that the log file directories don't exist. Does the /var/www/vhosts/domain.com/subdomains/sub/log/ directory exist?

Other than that, the configuration looks fine to me.

You'll also need to enable the new site you created.

As of Apache 2.2, I believe it ships with the command a2ensite. Run that command to enable the site, and it should get you going.

In simple terms, all it does is creating a symlink for the site from .../sites-available/ to .../sites-enabled/.

Sophira, thanks that solved it!

NeonNero, as I've mentioned in my previous post, it's already enabled.

Now that this is done, I've added the subdomain as an A record in Linode DNS Manager. Should I wait for the TTL to expire? Because right now, sub.domain.com doesn't resolve.

Update: Waiting for the TTL solved it, it now resolves fine. Thanks for the help guys.