Hi,
Just to come back to this, it's still a problem. Frequently affects forums.macrumors.com and a few other sites I use, while others never tend to be affected.
It's not a browser issue as Firefox has the same problem as Safari has. If I start a ping to forums.macrumors.com nothing happens (it's waiting for the lookup) until I open a new terminal and do sudo killall -9 mDNSResponder, at which point it springs into life.
Same if I'm browsing - if I'm trying to get to a site, or I'm on a site but images, for example, aren't loading because they're on a different hostname, I do sudo killall -9 mDNSResponder in Terminal and instantly everything kicks in.
I can reproduce it on my iMac at work and MacBook Air at home, both upgraded from Snow Leopard to Lion.
It doesn't happen on my new MacBook Pro, which had Lion preinstalled.
Driving me INSANE. Any ideas?
Yesterday I had my computer at 95º with some cores at 100% because mDNSResponder was doing something. I did shutdown all running apps and nothing worked until I restarted my macbook air. As all was working fine, I left my laptop on sleep mode. Today when I have come home, my computer was very hot at 95º with the same process mDNSResponder at 100%. Anybody knows what is happening with this process ?
Now I do not trust my computer in sleep mode.
The errors that I get are
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
05/03/12 17:56:51,026 mDNSResponder: ERROR: accept: 24 (Too many open files)
The only solution is to restart, but I do not know what is causing this problem. Any idea ?