Can and should I deploy ZFS before/when installing FreeBSD?

Question

FreeBSD

There are three x1Tb spindles and one 240Gb SSD. There is an idea to put spindles in RAID-Z and cache SSD. Is it better to do all this when installing FreeBSD? Or just roll the system on an SSD and only then assemble the file system on the spindles?

Answer 1

FYI: Freeha installer works on an already booted and working system. There's a console and everything. Once in the console, you can do whatever you want with the disks. For example, build a ZFS pool of the configuration you need.
On the other hand, the installer already knows how to install freu on ZFS, so in the general case, you don’t even need to climb into the console. It may not be possible to connect an SSD under L2ARC there, but you can definitely configure RAIDZ and install the system there. And L2ARC can be configured later by booting from a freshly installed system.