I have server with hardware RAID, i see that USB drive is recommended for OS installation, i understand that then you can have ZFS for all server disks without any hardware RAID.
But this server also has external 24x2.5" 2U storage which i ment to use for ZFS.
So is there any benefits to use USB drive as boot device, instead e.g. hardware RAID-1 with small SSD’s ?
All i can think is if server hardware fails, you can use USB to boot another server using this same 24x2.5" external storage and recover ZFS ?
I am not sure where you read that USB is recommended for the OS. I would argue that it’s the exact opposite. It’s not recommended, but it is a better choice than USB-stick, so I guess one could say there are worse choices.
Hardware RAID should be avoided no matter where you choose to install the OS.
If you are not using hardware RAID and your computer fails (but the drives are okay) it’s a simple thing to move the drives to a working chassis and pick up almost where you left off.
If your boot drive fails it’s also not a big deal if you made sure to save your configuration somewhere else, including encryption keys, as you can easily restore your configuration on a new OS install.
That used to be okay, but that was a long time ago now. Compared to before the OS now writes more than it used to so you will burn through the write endurance.
hardware raid should really be avoided… even for a boot-pool.
for what it’s worth, TrueNAS has the ability to easily mirror (or turn into a mirror) the boot-pool.
so while it might not be recommended, mirroring the boot-pool can mitigate the unreliability of flash drives a little bit. you should also move the “system dataset” to another pool, to reduce the writes. (I think this should be a general recommendation honestly, small SSDs that are often used for the boot-pool will just have less endurance.)
you should also consider USB to MSATA bridge boards that can often be a drop-in replacement for internal USB ports but support TRIM (which hardware raid almost never properly does!!) and allow you to use a real SSDs.
Oh, thank you, happy i asked, and i see your points for just using 1 OS boot disk, im old administrator when hardware raid was must to have
But i wan’t to keep anything as simple as possible, so i’ll go with 1 SSD for OS and 2.5" SSD disks for that 24x cabinet for ZFS that can be then expanded.
