CPU

[La Reine Margot]

We're actively keeping track of the CPU usage here and we noticed something of late.

At this moment I'm the only registered guest in the Forum

The CPU use is 28%

Why that high? We asked ourselves. There are 2303 non registered users ("guests") online, at this very moment. Who are they?

Most of those are bots. That's for sure.

Yesterday the CPU was at 99%!!!!

There were 4 registered users and over 6,000 "guests". That's what I call a bot attack.

The most 'guests' we had roaming the forum was back in January, when we had 12028 bots... that's a massive attack.

Our task now is to learn how to prevent those bots from attacking.

[Edukator]

I also noticed yesterday an intermittent slowdown of the site and got the same (blank page) error messages (meaning server overload due to too many simultaneous connections) than a few weeks ago just before the site crash. It doesn't looked reassuring...
You can simply NOT have 6.000 "guests" connected at the same time, only a bots attack could explain this. You should REALLY take some serious measures to prevent this and/or check with a good computer/website expert. During typing this I can only see one registered user (me) and 17 "guests".

[La Reine Margot]

The CPU usage right now is 4% with 150 'users'.

That's the normal most of the time.

We're checking to see when the sudden increase of bot activity happens.

We're not too worried about this because it doesn't happen all the time, just once in a while, but something causes it and we'll find out what.

[Edukator]

All looks good now, but...
If you can't find the source of BOT's attacks (which can happen again anytime) you should implement a way to prevent and block them, either by installing Robots.txt files, using CAPTCHA's, or both. There are also specialized bots-blocking applications but I have no idea how effective they are.