I've inherited a legacy server that's just a Celery 2G4Hz (those with almost no L2 cache) and otherwise pretty constrained. It's still running, although most services have been moved off it it's nice to have.
Now occasionally the box is unreachable for a few hours, and when I can login (per ssh) again, I see it has been under heavy load (mid to high two-digit figures), possibly due to the legacy trac plus svn viewer on there and search engine traffic (which I already tried to contain a bit).
Now sendmail has this nifty feature to disable delivery on load >= 8 and refuse socket connections on load >= 12 (of course configurable). Does Apache have something similar? The idea being to keep the load within a band that does still allow e.g. ssh logins (at load 10 it's probably possible just slow, at load 50 it's not possible period).
