On the Site Management screen, you can click the Suspend Site check box and Save Changes to make that vitual site be suspended. But when you clear the check box and Save Changes again and think everything will be as usual. Wrong!
The web pages and files of the vitural site are all gone. Why? Is it normal ?

When u suspend a site it makes all files hidden. Stops users logging in via ftp or telnet and stops them checking there email.

When u un-suspend them there files are visable again.

that is weird.

But my case was different from what you explained.
So, there must be something wrong in my server. :(