Clint is correct. I can allocate resources to whichever domains I need to in the most effective manner. So, of course, I allocate the most to the domains that are paying the bills around here. When the resources get stretched, I have it set to deny access to the lower priority sites so that the higher priority ones can still keep on operating.
I had 470 simultaneous logins at my main site. Not sure what was going on there but that most certainly caused the bogging down across the server.
If my main server gets too busy (which only happens if there is something really unusual going on), then I can always move this site to my other server.
Both are dual Xeon boxes, so they are NOT lightweight systems. I think what happens is that sometimes the search engine spiders go insane and flood sites. A search engine spider will often try to go to every post on the site via any links within the current page it is on. Get a hundred or so of them that are haywire and stuck in your site, you can really have loading problems in a hurry.
I would be interested to know the logic behind how those spiders actually work. They have to have a programmed lifespan otherwise they would be the scourge of the internet. Or maybe they already are, beats me. I couldn't get into my main site to even check to see who all of the users actually were in there when it peaked at 470. But I have seen some pretty unreal numbers on a lot of sites that keep track of max # of visitors. So I suspect something like this happens frequently.
Best thing to do if things get squirrely is to email me. I don't always stop in to check the pulse of my sites often enough to catch every problem quickly.
ahh... maybe the search engine spiders go nuts when someone is searching for posts that are only referenced here? i.e. normally this site would be the ten thousanth out of one billion hits for ".223" and "survival" but if you add the word "gunkid" it focuses here.
There are some very poorly written spiders out there... I wrote one once that I was all proud of (it was the first one I ever wrote), until the system guy at our company tracked me down. I was killing all the servers. I was generating like 100 threads on each server I went to. Ooops!
Oh, well. Learned a lot from it. But I'll probably never ever write one again, there's plenty to be found on the net you can use.