KeyWords: queue downtime

Reducing queue closure time before scheduled downtimes

Right now we are closing the queues 2.5 days before scheduled downtimes. It turns out that this is too much.

There is a big difference between the required walltime specified in your VO cards and the time the jobs actually take to run.

In this table, we gathered the information specified in the VO cards, and the statistical information taken from the last 5 months. Only jobs longer than 1 hour are considered.

value	lhcb	atlas	cms
CPUTIME in VO card	?	37.3	19.7
max CPUTIME in queue	32	48	24
PROPOSED CPUTIME in queue	32	42	24
WALLTIME in VO card	30.7	41.6	72
max WALLTIME defined in queue	48	48	72
PROPOSED WALLTIME defined in queue	48	42	72
max(avg,median) real job CPUTIME	21.8	3.5	3.5
max(avg,median) real job WALLTIME	25.8	4.9	5.5
95% of jobs finish below WALLTIME	48	19	20
PROPOSED closure time before downtime	48	20	20

(time specified in hours)

We should review the proposed closure time before downtime some time after changing the walltime defined in the lhcb queue, it will probably influence the statistics, since lhcb tried to use all the time it's given in the queue.

Also, please keep in mind that the walltime limit in the queue is the number that is published but it is relaxed. We give 6 additional hours of courtesy.