For security purposes we don't provision (dv) servers with root access enabled by default. Root access can easily be enabled via the admin section of the AccountCenter.
3. Click on Enable Root Access:
4. Enter and confirm your password after agreeing to the warning prompt. Use a password that is "strong" enough to pass our strength test as shown below and click Change:
You now have root access enabled on your server!
参考地址:
http://kb.mediatemple.net/questions/625/How+do+I+enable+root+access+to+my+(dv)?
plesk root ssh 开启 访问