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From: Sam Vilain (sam_at_vilain.net)
Date: Wed 24 Nov 2004 - 02:58:01 GMT

Jörn Engel wrote:
> On Tue, 23 November 2004 19:08:50 +0100, Jörn Engel wrote:
>>I love it when someone else already did the work. ;)
> Except when it's only partial. If implementation matches
> documentation, the fixed lower bound is 0 (zero). That's pretty low.
> Most people want to say something like "Ssh will always get 5% of cpu,
> no matter how many forkbombs explode. And the administrator's shell
> will inherit those 5%."

Actually it's the minimum timeslice, every maximum starvation interval.
Which is something like 0.05% of CPU, but its better than nothing; you
can get a lot done in a single slice these days. In extreme situations,
like the load gets above 500 (fewer with realtime processes), then the
anti-starvation system doesn't meet its guarantees (but nothing starves

So, set maximum process ulimits in your vservers to stop the system
being unusable in the case of a fork bomb.

If you increase the priority of the administrative daemons to -19, then
you will get what people *actually* want ;-) which is CPU time for
administration to come before all normal activity on the system. Even
with a load over 100 you should still be able to log in via ssh if it is
niced that high.

Sam Vilain, sam /\T vilain |><>T net, PGP key ID: 0x05B52F13
(include my PGP key ID in personal replies to avoid spam filtering)
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