MOO-cows Mailing List Archive
Re: DB crasher
--- Rich Connamacher wrote:
>Tell the wizzes of that moo to upgrade to 1.7.9p2 or the latest 1.8.0,
True, but there are quite a number of server hacks in there that prevent
the transition being easy. The server, I believe, is back in the 1.7.8
stone age, but there is no way to tell as ;version() returns
>because that already has a builtin task number monitor that's much more
>effecient than such a clock and won't have the problem of erroniously
>killing processes, because it simply won't let anyone begin any new
>processes over their task quota limit.
This is indeed better, I was simply mentioning an alternate way of dealing
with the problem.
>Although it's their moo so it's
>their call, running a clock like that is an _extremely_ messy band-aid
>fix to an old problem that doesn't exist anymore. What's worse, the
>chance that the moo will crash and loose data since the last checkpoint,
>or the 100% certainty that all processes will suddenly crash and almost
>certainly loose data in one way or another? I'd opt to simply let it crash.
Mosts tasks are trivial, any important tasks in progress will usually be
in such a way that eliminates the need for suspending.
>(Note that, if there really were a true fork bomb attack on that moo,
>unless the clock cycles so frequently as to lag the entire moo, the fork
>bomb could grow so fast that the clock will choke and die trying to
>keep up.. If they don't believe me, tell them to give me a prog bit on
>their moo and an okay to go ahead and crash it. Whoever wrote it
>must not understand exponential mathematics.)
I've only managed to slip one accidental fork bomb by it, and that was due
to several objects running verbs forked at 2 second intervals. (d'oh!)
As for the clock dying trying to keep up, unless someone added pre-emptive
multi-tasking when I wasn't looking, the server can kill ~15,000 tasks per
suspend(0). This ought to be enough to keep up with most fork bombs.
As for a prog bit, it is hard enough to get a prog bit there when you AREN'T
tring to crash the MOO . . .
I think the guy understood exponential math just fine, as your garden variety
fork bomb is stopped instantly.
- DB crasher
- From: Judy Anderson <email@example.com>
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