@iL if there's anything I can do to help please contact me, I will do what I can. Have you changed the DNS entry to an invalid address? If the attack is continuing that might possibly cause any proxies to get sick of the abusive traffic... worth a try.
Fixed it!
Well, it wrote "No space left on device" on every action (like creation file). But there was about 6Gb free.
What you think that means? I firstly thought that was some kind of "Read-only filesystem". Also maybe that's related to hoster's server migration somehow...
What really happened is all the inodes used. I also know that inodes can be finished, but never touched that. And now these's really 1,5M inodes have been used.
So, the server should be ok now.