hi, hm :( . . . okay Can you see the pages/sec value still decreasing?
Probarbly I am wrong . . . but if you start your crawl with a low number of threads (1 or 2), you should immediatly see a value which is very close to what you'd expect to see - considering the "server.delay" property. If this is not true --> I am wrong Regarding wikipedia: The english wikipedia has somewhat more than 1,900,000 articles now. This number doesn't take into account all the revisions that occured to them. If I recall it correctly a full dump of the english wikipedia would be around 600 GB. However, the actual content (the most up-todate articles) fits into a 2.5 GB download (bz2 compressed). This download excludes things like images, user discussions, revisions, and so on. But with this download you're ready-to-go to set-up your own wikipedia mirror. Cheers On 8/9/07, purpureleaf <[EMAIL PROTECTED]> wrote: > > > Hi, sounds that it is the cause, but I just tested it again. With > server.delay = 1s doesn't result in 1page/s, almost the same speed. > confused:( > I really didn't try to hammer wikipedia, just want to find a site with > enough pages to test. > > So with more than 12M pages of wikipedia, I guess it is almost impossible > to > crawl wikipedia on line. > How does google do this? > > > Martin Kuen wrote: > > > > hi there, > > > > the property "server.delay" is the delay for one site (e.g. wikipedia). > > So, > > if you have a delay of 0.5 you'll fetch 2 pages per second. > > > > In my opinion there is something about the fetcher's code that doesn't > > makes > > it obey this rule in the very beginning . . . probarbly at start-up 30 > > threads start immediatly without caring about this setting, which could > > cause a high pages/sec value in the beginning . . . but then the rule is > > applied correctly and this averaged-value (pages/sec) becomes corrected > in > > a > > step-by-step manner - however I have no evidence for this assumption. > > > > If you look around the Fetcher's code (or maybe at the http-plugin - > don't > > remember) you'll find a config-property called " > > protocol.plugin.check.blocking". If you set it to false you'll override > > the > > "server.delay" property. The result of this action is that you'll start > > "hammering" the wikipedia site. > > I tried to achieve the same by setting the "server.delay" to 0 . . . > > however > > . . . things didn't work well (I didn't investigate too much - I found > the > > " > > check.blocking" property, which worked?!). > > > > Btw. I propose that you should not start (large) crawls on the > > wikipedia-sites. The wiki guys don't like it. If you're just running a > > test > > and fetch a few pages . . . ok . . . but a crawl of 8 hours . . . hmm . > .. > > not just a few pages, right? > > Furthermore a "server.delay" of 0.5 doesn't really appear polite to me . > . > > . > > > > Ok, so what? If you're interested in indexing the wikipedia articles, > you > > can set-up wikipedia on your local computer . . . > > http://en.wikipedia.org/wiki/Wikipedia:Database_download > > Then you can run your fetch on your local machine or in your intranet > and > > you'll just be limited by the speed of the machine powering the > mediawiki > > application. I tried this with the German wikipedia dump and it took a > > little bit more than 33 hours (AMD Athlon 2600 dualcore, 2GB RAM, WinXP, > > java 1.5, nutch 0.9, ~614.000 articles, ~5.3 pages per second). I didn't > > really care about performance, so I think this could be faster. > > > > > > cheers > > > > > > > > > > > > On 8/9/07, purpureleaf <[EMAIL PROTECTED]> wrote: > >> > >> > >> Hi, thanks for your reply > >> > >> Yes I was fetching from wikipedia only, I do this just for test this > >> slowing > >> down effect. But not too much I think, 4pages/s, still gets slower and > >> slower, forever. So the fetcher is supposed to be slower than 1page/s > >> (per > >> site) ? > >> I watched my bandwith, it used less than 20k/s, way less than my > prodiver > >> feel easy. > >> > >> > >> > >> Dennis Kubes-2 wrote: > >> > > >> > If this is stalling on only a few fetching tasks check the logs, more > >> > than likely it is fetching many pages from a single site (i.e. > amazon, > >> > wikipedia, cnn) and the politeness settings (which you want to keep) > >> are > >> > slowing it down. > >> > > >> > If it is stalling on many task but a single machines check the > hardware > >> > for the machine. We have seed hard disk speed decrease dramatically > >> > right before they are going to die. On linux do something like > hdparm > >> > -tT /dev/hda where hda is the device to check. Average speeds for > Sata > >> > should be in the 75MBps range for disk reads and 7000+ range for > cached > >> > reads. > >> > > >> > Another thing is you may be maxing your bandwidth and your provider > is > >> > throttling you? > >> > > >> > Dennis KUbes > >> > > >> > purpureleaf wrote: > >> >> Hi, I have worked with nutch for sometime. One thing I am always > >> curious > >> >> is > >> >> when crawling, fetcher's speed will get slower and slower, no matter > >> what > >> >> configuration I use. > >> >> My last test get this: ( just one site to make the problem more > >> simple) > >> >> > >> >> OS : winxp > >> >> java : 1.6.0.2 > >> >> nutch: 0.9 > >> >> cpu : AMD 1800 > >> >> mem : 1G > >> >> network : 3m adsl > >> >> > >> >> site : wikipedia.org > >> >> threads per site :30 > >> >> server.delay : 0.5 > >> >> > >> >> It starts about 6page/s, but reduce to 4 in some minutes, then get > >> slower > >> >> and slower. I have run it for 8 hours, just 2page/s left, and it was > >> till > >> >> slowing down. > >> >> But if I stop it and start one other, it returns full speed (then > >> slows > >> >> down > >> >> again). I am ok with 2 pages/s for one site, but I do hope it will > >> keep > >> >> that > >> >> speed. > >> >> > >> >> I found there are some guys in this list has the same problem. But I > >> >> can't > >> >> find an answer. > >> >> If nutch designed to work this way? > >> >> > >> >> Thanks! > >> > > >> > > >> > >> -- > >> View this message in context: > >> > http://www.nabble.com/Fetcher-get-slower-and-slower-in-one-run-of-crawling-tf4241580.html#a12073371 > >> Sent from the Nutch - User mailing list archive at Nabble.com. > >> > >> > > > > > > -- > View this message in context: > http://www.nabble.com/Fetcher-get-slower-and-slower-in-one-run-of-crawling-tf4241580.html#a12076754 > Sent from the Nutch - User mailing list archive at Nabble.com. > >
