I've used ZFS on FreeBSD and loved it, but I only had FreeBSD as a server not as a desktop. With BTRFS on Fedora I was wondering (I'm a BTRFS noob) if it was possible to make a bootable encrypted (by Fedora Installer) mirror of two hard drives using BTRFS? Here's the kicker: would it be a good idea to take a 1TB SSD and a 1TB HDD and mirror them (read performance and "cheap" mirror for backups) or is that just asking for problems? Would using BTRFS this way cause data loss?
I'm just thinking of a few possibilities...
As for backups, what I would do with ZFS is add a third (usb) volume and "scrub" to "fix" the third volume, then once it was done, I would remove it (It would say degraded but I was fine with that). With BTRFS could I do the same? Add a third hard drive, "fix" it so it copies all the updates, and then remove it and put it somewhere safe.
Btrfs is well understood by grub so I don't think it should be a problem running an encrypted mirror. Make sure to install grub on both disks (or an additional USB stick or something like that) if you want to be able to boot if one dies.
A 1TB ssd disk is expensive. Think about it. You could get 2x1TB HDD and 2x250GB SSD and spend the same amount of money. Then you can put your OS and some work space on 100% SSD and have fast writes as well. It depends on your needs, but I would at least consider these kinds of scenarios first.
As to your ZFS backup strategy: are you sure that is trivial to import when needed? You can do send/receive with both ZFS and BTRFS, put an additional pool/filesystem on the USB disk, and get shorter resync times.
Yea after thinking about putting a 1TB SSD in RAID, it didn't make much sense, I was thinking instead 2 x 1TB and a 1 250GB SSD bcache, but after looking at bcache it seems "unstable" at the moment. My goal was to have a large home directory but still have bit-rot protection active all the time (or when I scrub).