SETI@home 2008 技术新闻

duwei

要是有中文就好了

BiscuiT

We seem to have gotten beyond the current period of high demand and back into a realm of working within our limited resources. Queues are filling or draining in a positive direction, albeit slowly. I did finally write a script to compute how many results passing through our validation queue are CUDA processed - currently roughly 3%. And speaking of that, I am now aware of the CUDA validation problems mentioned in other threads and I passed them along with screenshots, info, etc. to the proper authorities (i.e. Eric and Jeff).

At this time of year I do a lot of prep for upcoming server projects without enacting anythying too crazy, lest I break anything that's currently working just fine. For example, I'm building more RAID mirror pairs on the workunit storage server, but won't actually add them until the new year. We added enough space yesterday to hold us over until then. I'm also cleaning up the lab, labelling spare parts, placing things in boxes, organizing dozens of O'Reilly books currently stored inefficiently in stacks, etc. We also tend to "store up for the winter" - at some point soon we'll pull up a bunch of data from HPSS to keep splitters happy until the new year.

Thanks for all the holiday wishes/greetings, and please accept my likewise sentiments. For those thinking I'm going above and beyond the call of duty by working during vacation, don't give me too much credit. My vacation comes later.

- Matt


CUDA 的成果已经占到了3%，进展迅速。
另外CUDA的验证问题已经注意到了，应该很快会处理好。

[ 本帖最后由 BiscuiT 于 2008-12-25 11:00 编辑 ]

BiscuiT

One short holiday week is behind us, now here comes another one.

We did fairly well over the weekend, considering we were pretty much maxed out the whole time. The assimilator queue finally drained, thanks to splitters starting to chew on raw data files physically located on the new raw data storage server (as opposed to located on the same server as the science database), but also thanks to the validator queue falling behind.

In times of low resources we do have some knobs to turn to help squeeze more juice out of our embattled servers. Sometimes you have to roll up your sleeves (or, in this case, pull out a calculator) and determine what processes needs what resource, and which are claiming too much. After some investigation it was clear this time around we were giving httpd too much - and this is a tunable we have to adjust every so often, depending on how many people are connecting at any given time, and for how long - otherwise you have too many httpd listeners hanging out doing nothing eating up valuable memory/cpu. Anyway, long story short I reduced the number of validators from 6 to 4, moved the validator logs to a different filesystem (reduce i/o contention), and vastly reduced the number of httpd listeners. So far so good - that queue is draining (and therefore the assimilator queue is inflating again).

We will have the usual outage drill tomorrow, followed by another set of "days off."

- Matt

BiscuiT

Yep, we had our usual Tuesday outage. Nothing special, except that the result table is vastly bloated due to the back-end queues being clogged for one reason or another. So the "compression" part of our outage took an extra hour (roughly). So be it. Hopefully the wheels were greased enough to continue letting these drain without much intervention on my or Jeff's part. In any case except a slightly painful recovery as we continue to catch up. We're also pulling up a bunch more unanalyzed raw data to keep the splitters happy during the long weekend. Other than that today.. a lot of planning and preparing for various bigger projects to tackle once the holidays are over and we're all back in the lab - adding yet more workunit storage, reconfiguring database/raw data storage, adding more stuff to the closet, upgrading OSes, retiring older machines, bringing newer ones on line already. That's all well and good, except that Eric, Jeff, and I have three separate higher-priority tasks to tackle before anything else if possible. Those are (a) wrapping up all radar blanking efforts (we still get too many result overflows due to missed and therefore unblanked radar), (b) noise shaping (the noise we're injecting to reduce the effect of the radar is causing predictable and removable but nevertheless messy analysis artifacts), and (c) the NTPCker (the real-time candidate finder/reporter - so we might have something positive to mention come our 10th year anniversary in May).

That's it - the last tech news update (from me at least) for 2008. I'm already looking forward to 2009. Maybe we'll get some or all of the above done.

- Matt

Yujinliang

该是2009年了