Aaahaaa, I see. In this case, using an iMac, despite macOS X being FreeBSD ? you would have to check whether you are using the server version of OS X or the desktop version. I think throughput in server applications could be different here.
Regarding virtual servers, you can read my posts regarding VMware ESX, where I ported my Moodle 1.9 server in 2009 losing not only performance but also availabilty and stability. I had to migrate back to my physical server and buy another physical server the next year.
In the past years VMware ESX might have made improvements enough to make mySql not crash any more as it did all the time in 2009. For the moment being I am running only test-server-instances from Moodle 2.3 to Moodle 2.7 on a VMware ESX virtual machine. I have no figures for production as of today. I will be able to monitor that in a couple of months as another crew is remigrating our production Moodle onto VMware ESX virtual machines, one for mySql or postgreSQL and one for the apache web server. (as the high availability cluster did not perform as expected during the last 2 years)
Re-hosting your files elsewhere might be a problem in terms of access-rights. But why can't you leave them where they are and make your own backups with or without a database dump, completely bypassing the automatic course backups of Moodle? If you have only a few courses you can still instruct your teachers to do their course backups manually from time to time or do it yourself.
Technically speaking huge files might be too big to fit into a zip-archive. I read such a post on CentOS yesterday here. And again, zipping huge files might not be the correct backup-strategy anyway. So why would you not change it and stick to the Moodle course backups?
Rosario