Thank you, Dieter, for your valuable insights and information. I am forwarding this to my ISP.
--- Dieter Maurer <[EMAIL PROTECTED]> wrote: > Ken Ara wrote at 2006-9-5 07:47 -0700: > >... > >Of immediate concern to me is whether I can do > >anything to prevent this happening again. From time > to > >time, my Zope hangs, usually because of an attack > by a > >bad robot requesting lots of complex pages and > sending > >no-cache headers. Then I am able to restart Zope > and > >all is well. For a while, when these attacks were > >frequent, I had a crontab to zopectl restart every > >hour. > > There are solutions (I think "daemontools", but may > be wrong) > that can automate this more intelligently than a > cronjob. > > We have our own check server which polls Zope and if > it does > not respond in time restarts it. > > > >But this event was different and I would like to > know > >if anyone thinks that something I am doing wrong > could > >cause the Zope process to become 'unkillable' and > >require a reset of the machine. Has anyone else had > >this problem? > > Up to Python 2.3.4 and Python 2.4.0 (fixed in Python > 2.3.5 and Python 2.4.1), > a fatal signal (like "SIGSEGV") could bring Zope in > a state where > its main thread was killed but the child threads > were still alive. > These child threads could only be killed with "kill > -9". > > Although we now use Python 2.4.1, I have seen a > similar problem just > a few days ago. But almost surely, this has to do > with the > Java Virtual Machine which we now also integrate in > our Zope instances. > > > However, when even "kill -9" (as "root") is no > longer able to kill a process, > then the process is somewhere deep in the operating > system (where > signal handling is deactivated for consistency > reasons). > Usually, this indicates a network problem. > > And if your operating system is no longer ready to > shutdown, then > you have an even more fundamental problem -- maybe, > too, connected > to network problems. > > > I fear we cannot help you much -- as a intensive > analysis of your > system would be necessary in order to find the > causes of your > problems. > > >I would have liked to perform some diagnostic on > the > >machine in its stuck state, but neither I nor the > ISP > >knew where to start. > > Usually, one would start with an analysis of the > operating system > log files. > > If they do not tell anything, then one would check > what is still > working (e.g. is the console still responding, does > it still > observe the magic "CTRL-ALT-DEL" reboot key > sequence), which commands > fail and in what way, ... > > > > -- > Dieter > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com _______________________________________________ Zope maillist - Zope@zope.org http://mail.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope-dev )