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Profile B-Roy

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Message 3196 - Posted: 4 Oct 2004, 21:25:16 UTC

good to see the forums back up. even if some features are temporarily turned off (I hope that you are not using seti's definition of the word), it's nice too be able to see the stats again. I'm sure you will find the bottleneck and everyone can crunch through a lot of more wus to come.
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Zeeno

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Message 3298 - Posted: 6 Oct 2004, 23:39:42 UTC - in response to Message 3111.  
Last modified: 7 Oct 2004, 4:41:08 UTC

Out of curiosity, how many connections can it handle before it starts to break down?

Zeeno

> We had to disable even message boards for a while, the system was really stuck
> up. There is certainly a limit in how many database connections our server can
> handle at a time... But there was also bug in the main page which
> unnecessarily made database queries each time it was loaded. We fixed that,
> and also tuned the database server so now the forums are open again. Let's
> hope the system works better now.
>
> Results and Pending credits pages have been disabled until we see that we have
> enough capacity to handle them.
>
>
> Markku Degerholm
> LHC@home Admin
>
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Profile Nikolay A. Saharov

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Message 3328 - Posted: 7 Oct 2004, 20:01:32 UTC - in response to Message 3179.  

> Point is that those short WU's are needed just as much as the long ones. But
> we try to generate a mix of short and long work units such that the average is
> good, and we get the short ones crunched as well. But I think it will take a
> few more days before our physicists are able to start submitting those longer
> jobs.


Maybe it is possible to combine a few short WUs (i.e. 10?) into one? And calculate this monstrous WU 10 times, for every subWU? ;-)

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Profile Markku Degerholm

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Message 3410 - Posted: 9 Oct 2004, 15:46:45 UTC - in response to Message 3298.  

> Out of curiosity, how many connections can it handle before it starts to break
> down?

The problem is that the more there a connections, the longer they take to complete, and the more connections are needed.

Now that we system is working pretty nicely, we have 50 simultaneous DB connections and about 100 DB queries executing per second.

When the system was really slow, there was 400 connections which were able to do about 20 queries per second. After that we saw it wise to limit number of connections to 100.

We think now that bottleneck is amount of RAM and the disk system. After the database cannot be cached into available RAM, disk system performance starts to limit the performance. Most important aspect of disk performance is seek time, actual disk bandwidth is no problem.

Now that we have a new server (it should be serving on Monday) we should be able to serve current user base without problems.

Markku Degerholm
LHC@home Admin
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Guido Alexander Waldenmeier

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Message 3412 - Posted: 9 Oct 2004, 15:50:24 UTC

good news markku have a nice sunday ;-)
http://www.fs.fed.us/gpnf/volcanocams/msh/images/mshvolcanocam.jpg
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Profile B-Roy

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Message 3421 - Posted: 9 Oct 2004, 21:59:30 UTC

do you expect pending credits being turned on soon?
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Message boards : Number crunching : Server problems


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