[Beowulf] Question about maui scheduler and reservations on a node: logical AND or OR

Rahul Nabar rpnabar at gmail.com
Fri Jul 9 14:00:16 PDT 2010

If there are twin reservations set for the same timespan on a certain
node do they get ANDed or ORed?

setres -u userfoo -s '+5' -d '10:00:00' node1
setres -u userbar -s '+5' -d '10:00:00' node1

Will userfoo have access to the node or userbar or neither? Or is it
the first reservation that is always active?

Actual situation: Due to the way funding and priorities work on our
cluster there are weeks in which I am supposed to give exclusive
access to a certain user on a certain node. But the downside is that
sometimes for debugging or maintainance etc. I might have to use that
same node to run system jobs from a "maintainance" user. It would be
convenient of there was a way to tell the scheduler "Reserve node foo
for use by either foouser or baruser"

A related question:
showres shows me reservations but doesn't indicate what nodes these
have been made for. e.g.

stotz.58            User - -7:02:35:04 54:01:21:17 61:03:56:21    1/8
  Fri Jul  2 13:03:39
stotz.59            User - -7:02:35:04 54:01:21:17 61:03:56:21    1/8
  Fri Jul  2 13:03:39

But is there a way to know what node stotz.58 is active for?

PS. I had asked the first question a few weeks ago on the MAUI list
but received no replies hence I thought I should check if anyone on
this list has a tip. Sorry if someone gets the question twice!


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