Help with maxage / limiting default recording disk usage

Question

I've got 2 related questions:
1) Is it possible using -XX:StartFlightRecording and/or XX:FlightRecorderOptions to cause flight recording to only keep the last N minutes worth of recorded data on disk, so that any any point one can view data on the last N minutes worth of activity?  How?
2) What is the maxage parameter supposed to effect?  Reading http://docs.oracle.com/javase/7/docs/technotes/tools/solaris/java.html it seems like it's supposed to do the above, but I've not been able to see any difference in behavior with any of these args, and in particular, each of them is continuing to fill up the /tmp dir. with .jfc files well past the maxage limit.
No maxage: -XX:+UnlockCommercialFeatures -XX:+FlightRecorder -XX:FlightRecorderOptions=defaultrecording=false,dumponexit=true,dumponexitpath=/tmp,loglevel=trace
Maxage on StartFlightRecording: -XX:+UnlockCommercialFeatures -XX:+FlightRecorder -XX:StartFlightRecording=maxage=1m -XX:FlightRecorderOptions=defaultrecording=false,dumponexit=true,dumponexitpath=/tmp,loglevel=trace
Maxage on FlightRecorderOptions: -XX:+UnlockCommercialFeatures -XX:+FlightRecorder -XX:FlightRecorderOptions=defaultrecording=false,dumponexit=true,dumponexitpath=/tmp,loglevel=trace,maxage=1m
thx,
Chris

Answer 1

"Is it correct that the XX:StartFlightRecording options are meant to only apply to a special start recording (that starts at server start time), while the XX:FlightRecorderOptions are meant to apply to any/all recordings"
-XX:FlightRecorderOptions is meant to configure global settings, but there are also options that controls the default in-memory recording (called "Hotspot default"), which can be turned on by setting defaultrecording=true. Since Flight Recorder records the union of all ongoing recordings, it will in practise apply to other recordings as well.
"The settings=path option seems to have no effect when given to XX:FlightRecorderOptions, even though it's listed in the documentation page above as being a supported option.  When I use settings=path with XX:FlightRecorderOptions, I still get the default settings.  Is this a known implementation or documentation bug?"
It's a known bug, as a workaround you can replace the file named default.jfc in JRE_HOME/lib/jfr with the settings file you want, i.e profile.jfc
"With both XX:StartFlightRecording and XX:FlightRecorderOptions, what's the behavior when defaultrecording=false?  "
No default (in-memory) recording will be started
"The documentation says "Specifies whether the recording is a continuous background recording or it runs for a limited time. By default, this parameter is set to false (recording runs for a limited time)." What is this limited time (how long)?  And is it a limited time forward from the beginning, or backwards from the current time?  Why is this setting even needed given the maxage, maxsize, and duration settings?"
It's incorrect, defaultrecording=true is just a convenience option for starting the default in-memory recording. There is no limit put in place if you set it to false.
If you want to use a disk repository, you can ignore all options that includes the word "default" and just use -XX:StartFlightRecording.