[Beowulf] Definition of HPC

Max R. Dechantsreiter max at performancejones.com
Wed Apr 17 14:32:28 PDT 2013


Joe,

> So, I am sorry ... if you *require* root to perform your work on a
> regular basis, chances are, you are one misstep from misfortune, and its
> quite likely to be self-inflicted.

What about dropping page cache?  What about setting up to
run in "turbo mode" (with Intel processors)?  There are a
number of relatively minor functions accessible only via
root (or sudo) that could be important for performance
testing.

Administrators don't have to give root access to everybody,
just because they give it to a few - it's not a democracy.
But I should be able to lobby for my needs, and expect my
actions to be carefully scrutinized, knowing consequences
of abuse would be serious and far-ranging.  You've heard of
system logs, I presume....

> But back to the running with scissors down broken staircases, in the
> dark, with low coefficients of friction on the stable steps, and many
> missing or unstable steps ... that is running as root.  Make sure you
> have good, recent backups, and you test that your backups are recent,
> and correct, before you go break something important. And if you rely
> upon external support, make darned sure they have a clue.

Running as root always makes me very nervous, which is why
I avoid it at all costs.

In fact almost all of what I need could be wrapped either
in sudo commands, or in special batch queues having the
desired properties.  THE PROBLEM with shared resources is
that their administrators are too hidebound to negotiate
such needs, in far too many cases.

> Running as root?  Yeah, its that bad.  Just say no.

Are you setting yourself up as arbiter of who should and
who should not run as root?  Please - respect those of us
who have the capabilities, experience, and juice to do so
(when cirumstances demand it).

Max


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