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muto1899
25.01.2011, 00:21
Zur Info, habe ich gerade gefunden

While we appreciate everyone wanting to crunch more MilkyWay@Home by increasing their cache limits; this is part of the reason why we've had so many server problems lately with an unresponsive validator. Mainly, our machine/database is not fast enough to keep up with the additional amount of workunits this is causing in the database. So if anyone is modifying their BOINC client to artificially increase their cache we're asking you to stop so the project will be more stable (until we can further improve our hardware). A few of the really offending clients (who have cached 1k+ workunits) are being banned as they haven't responded to us, and they're hurting everyones ability to crunch the project as a whole.
So in short, we need you guys to work with us as we're working with limited hardware that can't handle more than 500k+ workunits at a time -- our cache is low partially for this reason. Second, as we've said in a bunch of previous threads in the past, due to the nature of the science we're doing at the project we need a low cache because this really improves the quality of the work you guys report.
As you (hopefully) know by now, we search for structure and try to optimize parameters to fit that structure within the Milky Way galaxy. And lately we've been also doing N-Body simulation of the formation of those structures. What your workunits are doing is trying to find the optimal set of parameters for those N-Body simulations to end up best representing our sky survey data or to fit those different structures (like dwarf galaxy tidal streams) from that data.
To do this, we use strategies which mimic evolution. The server keeps track of a population of good potential solutions to these problems, and then generates workunits by mutating some solutions, and using others to create offspring. You guys crunch the data and return the result -- if it's a good one we insert it into the population which improves as a whole. Over time, we get very very good solutions which aren't really possible using other deterministic approaches.
If people have large caches, that means the work they're crunching can come from very old versions of those populations which have since evolved quite a bit away from where they were when the user filled up their cache. When they return the results there's a lower chance for the results to improve the population of results we're currently working with.
So that's why our cache is so low, and we'd really appreciate it if you worked with us on this. There are other great BOINC projects out there which can help fill in missing crunch time when we go down, and the BOINC client can definitely handle running more than one at a time. So it might not be too bad to explore some of the other great research going on out there. :)
Thanks again for your time and understanding,
--Travis