[ 
http://issues.apache.org/jira/browse/NUTCH-272?page=comments#action_12412621 ] 

Ken Krugler commented on NUTCH-272:
-----------------------------------

The generate.max.per.host parameter does work, but with the following 
limitations that we've run into:

1. The current code uses the entire hostname when deciding max links/host. 
There are a lot of spammy sites out there that have URLs with the form 
xxxx-somedomain.com, where xxxx is essentially a random number.

We've got code that does a better job of deriving the true "base' domain name, 
but then there's...

2. Sites that actually have many IP addresses (not sure if they're in a common 
subnet block or not), where the domain name is xxxx-somedomain.com.

Because of these two link farm techniques, we ran into cases of 100K links 
essentially being fetched from the same spam-laden domain, even with a 
generate.max.per.host setting of 50, after about 40+ loops.

And what's really unfortunate is that many of these sites are low-bandwidth 
hosters in Korea and China, so your crawl speed drops dramatically because 
you're spending all your time waiting for worthless bytes to arrive.

> Max. pages to crawl/fetch per site (emergency limit)
> ----------------------------------------------------
>
>          Key: NUTCH-272
>          URL: http://issues.apache.org/jira/browse/NUTCH-272
>      Project: Nutch
>         Type: Improvement

>     Reporter: Stefan Neufeind

>
> If I'm right, there is no way in place right now for setting an "emergency 
> limit" to fetch a certain max. number of pages per site. Is there an "easy" 
> way to implement such a limit, maybe as a plugin?

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