[Swift-user] Please clarify throttle parameters for coasters and GT2 issues

[Mihael Hategan]

On Thu, 2009-04-02 at 21:20 -0500, Michael Wilde wrote:
> I (and colleagues Im working with) have a few related questions:
> 
> At some point guidelines were posted regarding "safe" throttle values 
> for sending to GT2 GRAM sites. I recall "max 40 jobs". Can you clarify 
> if that number is still the best practice,

Yes. GT2 hasn't changed much since.

>  and how to the 4-5 throttle 
> parameters to conform?

The defaults are pretty much geared towards the gt2/gridftp combo.

> 
> Then, do those same values apply to coasters?

No. Throttles in the range of 32-256 (or maybe even more) are not
unreasonable with coasters.

> 
> Finally, with the recent successes in high-volume coaster runs on Ranger 
> - 190K jobs in ~ 5 hours, and even the earlier runs of 65K jobs - how 
> were those achieved without tripping into the GRAM overhead limits, 
> given that Ranger as far as I know has only GT2 GRAM and even submitting 
> locallly to SGE must go through GRAM since we have no direct SGE 
> provider?  Are the "safe" limits for Ranger simply higer,or is there 
> something else involved that makes this practical?  In other words, 
> please share and post how to get lots of jobs through Ranger.

coasterWorkersPerNode=16. That gives you 640 cpus with exactly 40 gram
jobs.