After downloading FreeBSD-12.0-RELEASE-amd64-disc1.iso to burn a CDROM I discover that it is far too big for CDROM capacity 851MB!
871808 -rw-r--r-- 1 lolo wheel 892467200 Dec 12 17:51 FreeBSD-12.0-RELEASE-amd64-disc1.iso
I had to burn a DVD and if a dvd is needed, the dvd1 iso is more interesting.
this make the amd64 disk1 iso useless.
This is known for 12.0. There was nothing that could have been excluded from the disc1.iso image to reduce the size, while keeping the 'Live CD' mode useful for system recovery.
100-pack CD-R: $14 
100-pack DVD-R: $14.59 
DVDs are so cheap just from an absolute standpoint (much less $/GB) that I'm not sure CDs make any sense anymore. Perhaps we should just retire "CD"-specific media entirely.
(In reply to Conrad Meyer from comment #2)
I think we should update our Handbook '2.3.1. Prepare the Installation Media' chapter to use DVD.
It might be possible to provide zfs-based FreeBSD .iso images with lz4 compression enabled on creation - this would probably cut image sizes in half or thereabouts
I don't think ZFS-based boot media are a good idea: CD images are likely used on old systems that won't have enough RAM for ZFS anyway. How about using geom_uzip(4) to compress the base system instead? This might make the set up a bit more complicated though.