RMAN not compressing controlfile autobackups

[Rich J]

Howdy,

So I ran into a storage space issue with our DR solution, where I found
that RMAN control file backups are large-ish portion. Using v11.2 (for
now), I have something similar to this in my RMAN configurations:

CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO
'/blah/blah/blah/%F';
CONFIGURE DEVICE TYPE DISK PARALLELISM 4 BACKUP TYPE TO COMPRESSED
BACKUPSET;

But the control file backups are obviously not being compressed, as I
can gzip a copy of one to get a 95% compression ratio.

I haven't been able to find anything in the RMAN manuals, MOS, or the
Freeman/Hart RMAN book relating to controlfile compression, other than a
single example RMAN command. Which brings up two questions:

1) How does one go about compressing the controlfile in scripted RMAN
backups? As a separate command (e.g. with AUTOBACKUP off)?

2) Given that it's difficult to find information on controlfile
compression, should I use it?

Thanks!
Rich