Download Maui Administrator`s Guide - Adaptive Computing Documentation

# kill resource hogs
RESOURCEUTILIZATIONPOLICY ALWAYS
RESOURCEUTILIZATIONACTION CANCEL
# notify user of job events
NOTIFYSCRIPT
-----
tools/notify.pl
Monitoring:
The most difficult aspects of this environment are properly 'reserving' space for the
untracked 'background' load. Since this load is outside the viewing/control of the
scheduler/resource manager, there are no constraints on what it can do. It could instant grow
and overwhelm the machine, or just as easily disappear. The parameter
'NODEUNTRACKEDLOADFACTOR' provides 'slack' for this background load to grow and
shrink. However, since there is now control over the load, the effectiveness of this parameter
will depend on the statistical behavior of this load. The greater the value, the more slack
provided, the less likely the system is to be overcommitted; however, a larger value also
means more resources are in this 'reserve' which are unavailable for scheduling. The right
solution is to migrate the users over to the batch system or provide them with a constrained
resource 'box' to play in, either through a processor partition, another system, or via a logical
software system. The value in the 'box' is that it prevents this unpredictable background load
from wreaking havoc with an otherwise sane dedicated resource reservation system. Maui
can reserve resource for jobs according to all info currently available. However the
unpredictable nature of the background load may mean those resources are not available
when they should be resulting in cancelled reservations and the inability to enforce site
policies and priorities.
The second aspect of this environment which must be monitored is the trade-off between
high job throughput and job starvation. The 'locally greedy' approach of favoring the
smallest, shortest jobs will have a negative effect on larger and longer jobs. The large, long
jobs which have been queued for some time can be pushed to the front of the queue by
increasing the QUEUETIMEWEIGHT factor until a satisfactory balance is achieved.
Conclusions:
Mixed batch/non-batch systems are very, very nasty. :)
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