If a database that was created by a mongod running with --smallfiles is later opened by a mongod running without --smallfiles, an "info" message is logged for each data file smaller than 64 MB. The message shows the size but not the filename. It would make the message more useful if it included the filename; this way, someone reading the log would know what database triggered the message.

Fri Oct 19 16:01:13 [conn1] info openExisting file size 16777216 but cmdLine.smallfiles=false
Fri Oct 19 16:01:13 [conn1] info openExisting file size 33554432 but cmdLine.smallfiles=false