Currently trying to index a 2.8Gb log cisco firewall log file. It doesn't seem to be progressing beyond saving over an hour. Splunks on a decent box and isn't under high load. What's the maximim file size supported?
I don't think there is a specific maximum file size, beyond the underlying operating system / filesystem limits. You might find use in amrit's filestatus tool, which gives a realtime view into Splunk's tailing processor. See http://blogs.splunk.com/2011/01/02/did-i-miss-christmas-2/ for where to find it and how to use it.