From sysinstall to ZFS-only configuration.

I’d like to share how we set up new servers at my company.

As you know, sysinstall currently doesn’t support ZFS or GEOM configuration, but I’ll show you how to convert system installed with sysinstall to ZFS-only server. Even if you don’t want to follow all the steps, please take a look at ZFS datasets layout, which after several modifications I consider quite optimal for FreeBSD.
After doing all the steps below your system will use GPT partitions, encrypted+mirrored swap and mirrored ZFS system pool.
I’m assuming your server contains two identical disks (ada0 and ada1).
Start from installing FreeBSD on the first disk using regular installation CD/DVD. Choose exactly one slice and exactly one partition. Reboot.
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