I have a iMac 2015 with Retina 5K display and OS X Yosemite installed. I intend to install Linux Mint as well as Windows 7 or in other sense triple boot all these three OS.
I did find some instructions here and hopefully I'll manage from there
The real concern is that once I am done installing all the three OS on the iMac, is there anyway I can create a backup Image of the hard drive with all the installations on it so that I can just restore the image on other systems I intend to install them on later ?