[Swift-devel] Re: replication vs site score

[Ben Clifford]

even more rambling... in the context of a scheduler that is doing things 
like prioritising jobs based on more than the order that Swift happened to 
submit them (hopefully I will have a student for this in the summer), I 
think a replicant job should be pushed toward later execution rather than 
earlier execution to reduce the number of replicant jobs in the system at 
any one time.

This is because I suspect (though I have gathered no numerical evidence) 
that given the choice between submitting a fresh job and a replicant job 
(making up terminology here too... mmm), it is almost always better to 
submit the fresh job. Either we end up submitting the replicant job 
eventually (in which case we are no worse off than if we submitted the 
replicant first and then a fresh job); or by delaying the replicant job we 
give that replicant's original a chance to start running and thus do not 
discard our precious time-and-load-dollars that we have already spent on 
queueing that replicant's original.

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