The central log can be found on index03 at /mnt/storage/var/log/. The central.log file itself contains the feed (import, update, …) related logging of one day. You can see the logging of the past 14 days by looking into the central.log.<index>.gz files with central.log.1.gz containing yesterdays logging.
Since the file(s) contain data from different modules you might want to search for different things. Here you find an (incomplete) list of useful commands for searching. In case you search in the .gz files replace grep with zgrep (only in the file access not after pipes).
grep ERROR /mnt/storage/var/log/central.log | grep “image-server”grep “certificate verify failed” central.loggrep “feed_import” central.log | grep “ 3530:”Keywords: v3 lilly feed