crawler.verbosity (collection.cfg setting)
This parameter specifies the verbosity setting for the webcrawler when it writes to its log files. The higher the number the higher the verbosity and the more detailed messages it will write out.
The range of values is: 0-6. Setting the value to zero will result in only error messages being written out, setting it to 6 will result in the maximum number of messages being written out.
You may set this value higher if you are trying to debug a crawling issue, but normally it should be left at the default as otherwise it may generate very large log files.