Installation with ZFS - how long does it normally take?

[tdalej]

As I said, I don't know much about ZFS. 
500GB of space is overkill for my setup, 855GB is even more overkill.

I only brought this up because another product lists ZFS first in the list of filesystem options and creates an identically configured ZFS filesystem in a fraction (very small fraction) of the time.

If I were creating an mdadm RAID it's the difference between using --assume-clean and not.
Is there a comparable flag for ZFS?

It's not _that_ critical of an issue as I will only install maybe a couple more times before try a recovery install before I put this in use.

What bothers me a _lot_ more is the routing issues I have hit :/

[cookiemonster]

Could be more critical than you think. Can you afford this rebuild time once is in production? If yes, no worries.
It should not take long, just a few minutes. If it doesn't, something is wrong and is not zfs itself.
About storage requirements: With your spec, I would use only two discs in mirror config for OS.
In your shoes, I'd like to know why it does what it does before commissionig for production use.

[CJ]

I agree with CM.  Something is screwy with your system.  It could be that one of your discs is failing or something else.

I would start with SMART tests and maybe even a destructive burn in test for the drives, as well as running a memory test.