When I run
/dspace/bin/dspace stats-log-converter -m -i /dspace/log/dspace.log* -o statistics.log -n
only the first file matched is converted (e.g. dspace.log.2012-09-12).
I'm judging I'm not the only one who has this problem because I found this page suggesting a workaround:
That workaround is inefficient because it requires starting up the JVM once for each day of statistics processed.