[Swift-devel] Coaster capabilities for release 0.9

[Ben Clifford]

On Wed, 22 Apr 2009, Michael Wilde wrote:

> 1) slow start starts too slow. Maybe the user needs a simple setting of how
> aggressive to schedule, where the automated default is somewhat more
> aggressive than the current default.
> 
> And it should be based on job starting, not job completion - I dont know if it
> is, but it *seemed* to me it was not. I might be mistaken.

Its based on final completion.

The low defaults are deliberate because people were getting upset about 
Swift overloading gram2 installations.

I have a TODO to make the two main load parameters more user friendly: 
most likely being the settings, as integers:
   * maximum number of jobs to run on this site
   * how many jobs to run at once should the scheduler start with

The defaults for those are 20 and 1 at present (though specified in the 
existing different parameter space)

Thsoe seem to be the main two parameters people want to change, in my 
experience, and I think changing them to the above two bullet points is a 
helpful thing to do.

> BUT end uses should not have to dicker with these settings for every site. WE
> need to provide site definitions for TG, OSG, etc (ie "supported" sites) and
> we need documentation that tells a user (eg a "swift admin") how to do this
> for new sites.

For gram2 sites, the defaults are the settings I recommend. Thats why they 
are set there. I have no confidence in any OSG site being really able to 
deal with a higher load without people coming back and blaming swift for 
overloading.

Probably the docs could have a nice table of what is recommended for the 
different providers and situations. When something autogenerates a site, 
it can probably be made to set it to the recommended defaults for that 
site if it has no other information.

Almost all other execution mechanisms can handle substantially higher 
loads, but given the poor publicity generated when someone blows up a site 
using Swift, I am against changing the defaults for gram2.

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