Raymond's questions

I read a book about security in web servers and I found this:

If your web server has the ability to write to the files in your WordPress directories, then the automatic upgrade functionality works. If not,WordPress prompts for your FTP credentials to update the files for you. Both of these situations concern us. In general, your web user should not have write permissions to your entire web root. This is just asking for trouble, especially on a shared hosting platform; realizing, of course, that certain directories such as the uploads folder must be writable by the web user in order to function.

Professional Wordpress by Hal Stern

What I want to ask is who is the web user of my server? I'm using Nginx and PHP5-FPM. The web root folder of my server is owned by raymond:raymond. Nginx is running as nginx:nginx and PHP5-FPM's listen.owner is set to raymond and listen.group is also set to raymond

The web root directory permissions is drwxr-x-r-x, my public_html is also set like that.

So how can I know if I'm in trouble with this setup?

BTW, I'm using Linode for my host! I'm not in a shared hosting environment. Thanks!

I don't understand why my htop meter is full already. I'm not even running some task. Here's the screenshot of my htop:

The green meter shows used memory, the blue meter shows buffers, the yellow meter shows cache. it seems that the cache have used up all my memory here. Or am I just confused? Because the numeric number shows 48/494MB.

So what is happening here? Should I increase the memory of my server?

I'm going to run nginx, php and wordpress. is this server enough to handle this setup?