Matt,
Next you switch from prefork to worker mpm on Apache make sure it is actually allowed to spawn child processes.
OK?
Whatever that means :?
But thanks anyway Matt, your efforts, as ever, are much appreciated!
(appled)
Seems to be up and down like a yo-yo. :(
Did you flick the stability switch the wrong way?
I think it likes to change itself :/
I've put it back on prefork mpm because worker mpm seems to go nuts and I can't find a good balance of performance and resource usage.
We're still on FastCGI PHP for now, even though that doesn't appear to actually do what I thought it did, but it does save us lots of memory which is good.