Hi!
For the first few months I’ve been running TrueNAS from a USB memory. Today, I’ll finally add a SSD for the system to my server.
I thought I just could install the drive and add it as a mirror in the boot pool. Turns out things wasn’t that simple.
What do you suggest, both in setup and getting there?
Thanks!
I personally use a 2-way mirror of 16g optanes connected via usb (and adapters) for my truenas and for my proxmox. Works ok. Although 16g is not much for truenas, as each boot env is using ~2.7-3G, and there is only 13G of usable space.
I think it depends on the HW configuration, but wasting one sata port (or even two) just for boot looks unreasonable to me.
Unless there is a remote access reason to have redundancy for the boot pool, a single SSD will be perfectly fine. Just keep a copy of your configuration file somewhere safe and you can quickly and easily restore your system.
No remote access needs, but from times to times quite hectic so prefer to go with a mirror so that I don’t have to reinstall immediately. 
Just so you are aware, there is one pitfall when using a mirror in this manor:
If the normal bootable drive hangs during the boot process, maybe due to a corrupt file, it will not fail over to the other drive.
Your best bet if you want to use a mirror is to use IPMI so you can remote into the motherboard if you must go the remote route, or just enter your BIOS and reconfigure, and change the boot drive, then the other drive can start working correctly. This is why I mentioned the Remote thing.
So long as you realize this one significant pitfall, then you are good to go. And if switching to the mirrored drives fails, again, keep a copy of your TrueNAS config file, it will save your butt when things go south. And as I said, recovery is fast. You need to install TrueNAS to a new boot drive, then restore the config file, that is it. But it does require 10 minutes or so to do.
Either way you do it works.
Ah, thanks for explaining this caveat! Obvious once you mention it, but I didn’t think about the fact that the system has it’s boot order set in bios – so the mirror will only be automatically useful when the first boot drive fails in a more severe way. (Weekly backups already in place thanks to your script, btw!)
