[Labs-l] Important reminders for tool-labs users!

[Marc A. Pelletier]

== Bastion hosts ==

Do not run jobs on the bastion hosts (-login and -dev) unless it is to
test interactively.  All jobs must be sent to the grid, which does
balancing and scheduling.

In particular, this means cron jobs: nothing in your crontab should last
more than a few seconds at the very most -- anything more needs to be
scheduled as a job.

The rule is simple:  if it isn't interactive, then it shouldn't be run
on a bastion.  Doing so destroys interactive performance for the other
users, and consumes resources that do not scale (unlike the grid, which
does).

== Cron ==

A second point is cron jobs; /please/ try to limit the frequency at
which you invoke cron; every hour or half-hour is fine.  Every ten or
five minutes is pushing it.  Every minute is right out.

As a rule, anything that needs to check for something to do at such high
frequencies is going to be /much/ more efficient and gentle on resources
if it runs continuously and /sleeps/ for those brief periods rather than
fire up new processes.  (And, being continuous, should be sent to the
grid -- see above).

I would much rather not have to start editing crontabs preemptively to
disable them.  If you are unsure how to adjust your tasks, don't
hesitate to contact me or another admin by email or on IRC -- we'll be
glad to help.

-- Marc