This took a bit for me to figure out, had me banging my head for a little awhile. I’m on Media Temple (dv) Dedicated Virtual hosting and have two installations of WordPress Multi-User (MU) each pointing to a different IP address. One day, I was trying to upload a file via FireZilla FTP to my /wp-contents/blogs.dir/[blog.id]/ folder and it said permission denied. I thought that was odd, but stupidly did a CHOWN on the entire httpdocs folder (this is Media Temple’s public_html folder) to set it to the account user. Problem solved. Unfortunately then the WordPress Media uploader stopped function and I was getting the message: “The uploaded file could not be moved to the upload folder.”

So did a Google search and found a few informative forum threads discussing the problem and possible solutions:

• CHMOD the wp-content folder to 777, which is a HUGE security risk. I don’t recommend you do this, but it works for some people.
• CHMOD the wp-content folder to 755, doesn’t really work
• CHOWN the blogs.dir folder to nobody, BINGO!

So the answer turns out to be that the blogs.dir folder’s ownership has to be set to nobody or essentially the server. If the ownership is set to the user account, you are able to upload content to the blogs.dir folder, but WordPress Media Uploader can no longer. So to solve the problem, I SSH into the server and browsed to the wp-content folder and:

chown apache blogs.dir -R

Afterwards, the WordPress Media Uploader was able to upload files once again. It’s funny because WPMU version 2.8.1 and prior never had an issue like this, so not sure what was changed.

2009-01-25 UPDATE: So I ran into the permissions issue again. Oddly, it cropped up after I added another account on my MediaTemple (dv). I followed my steps above and it no longer seemed to work for me. After spending a couple of frustrating hours on Google for a solution, I decided to take some people’s advice and turn-off Safe_Mode (read more). Obviously there are some inherent security issues with doing so, but since I don’t grant anyone else access to my web server, it shouldn’t be a huge problem. I also had to do:

chown apache:apache blogs.dir -R

since that was the account my web-server uses to write. Things are now working as they should.

2011-01-14 UPDATE: See the directions on this website as well: http://hereshowi.com/wordpress/fix-wordpress-permissions-on-mediatemple-dv-server.

There are some rare cases that I do need to have more than 1 FTP account and while you can’t do anything about it with Plesk, fortunately by SSHing into your (dv), you can create multiple FTP accounts. I found these directions on Marc Grabanski’s website who found the directions on Parallels’ knowledge base and I’m going to reproduce the directions here on my website for my reference (and others). And in case it isn’t obvious, you replace USER_NAME with the actual user name you wish to use.

[sourcecode language="bash"]
ssh domain.tld -l root
/usr/sbin/useradd -d /your_domain/some/location -s /bin/false USER_NAME
/usr/sbin/usermod -G psacln USER_NAME
chmod 755 $HTTPD_VHOSTS_D/your_domain/some/location
chown USER_NAME:psacln $HTTPD_VHOSTS_D/your_domain/some/location
chmod 751 $HTTPD_VHOSTS_D/your_domain/httpdocs
passwd USER_NAME
[/sourcecode]

Also one user, Dan, noted that if you don’t set the user password first, it chowns it to the user without a password and won’t allow you to connect, so he recommends this:

[sourcecode language="bash"]
ssh domain.tld -l root
/usr/sbin/useradd -d /your_domain/some/location -s /bin/false USER_NAME
passwd USER_NAME
/usr/sbin/usermod -G psacln USER_NAME
chmod 755 $HTTPD_VHOSTS_D/your_domain/some/location
chown USER_NAME:psacln $HTTPD_VHOSTS_D/your_domain/some/location
chmod 751 $HTTPD_VHOSTS_D/your_domain/httpdocs
[/sourcecode]

Barry has a number of great posts on his blog that might be helpful for the WordPress developer such as:

• How to make a more stylish search widget
• Hacking KSES
• How To: WordPress 2.3 upgrade via SVN on Media Temple Grid Server
• Snippet of the day: Selective code loading for plugins

So if you get a chance, check out Barry’s blog at http://blog.clearskys.net and be sure to bookmark it for future reference, I did.