Are there limitations to log file size?
Urchin's log processing engine can process webserver logs that are larger than 2GB, regardless of whether they are compressed with bzip (.bz2), gzip (.gz), or zip (.zip) since Urchin uncompresses the files using the zlib library.
However, Urchin's log processing engine uses the unzip/zip binaries in the util directory to create backups and archives of the reporting data for each profile. If the reporting data for a month is large enough to cause the zip file to exceed 2GB, Urchin will not be able to make backups or archives, and log processing will fail unless automatic backups and archives are disabled. In this case, you will need to manually back up the files with some other external utility.