[Condor-users] Preemption question

["Miskell, Craig" <Craig.Miskell@xxxxxxxxxxxxxxxx>]

Hi,
	To follow on from the "Preemption question" thread of March this
year
(https://lists.cs.wisc.edu/archive/condor-users/2006-March/msg00353.shtm
l), I have run into an interesting situation.  
I, too, thought I had disabled pre-emption with:
PREEMPT                 = FALSE

Lo and behold, some jobs got pre-empted last night (the first time my
pool has had any real contention for resources).  From my reading of the
previous thread, this can potentially happen when PREEMPT is false, but
only if the machine has a RANK expression which results in it preferring
a different job to the one currently running.  If that understanding is
correct, then something weird is going on, as all my startds have a Rank
of 0 (I've done nothing special).

Interestingly, in this case the preferred/pre-empting job had a Rank =
Mips, whereas the pre-empted/evicted job had a Rank of 0.  This may be a
red-herring, but does seem suspiciously related.  Should the job Rank
have any effect on preemption (I would have thought it wouldn't even be
considered until the Negotiator had decided that a given Startd was a
candidate for satisfying the claim).

I'm going to set MaxJobRetirementTime to something large as a
pre-emptive (pun intended) strike against such things happening again,
but I'm curious as to why this might have happened at all, as it
indicates a lack of understanding on my part.

Condor version is 6.7.18, running on linux (x86_64 and i386).

Craig Miskell,
Technical Support,
AgResearch Invermay
03 489-9279
"Cynical" is a term invented by optimists to describe realists.
=======================================================================
Attention: The information contained in this message and/or attachments
from AgResearch Limited is intended only for the persons or entities
to which it is addressed and may contain confidential and/or privileged
material. Any review, retransmission, dissemination or other use of, or
taking of any action in reliance upon, this information by persons or
entities other than the intended recipients is prohibited by AgResearch
Limited. If you have received this message in error, please notify the
sender immediately.
=======================================================================