gpart add -t zfs

[balanga]

What does -t zfs as in gpart add -t zfs actually do? I assumed it created a ZFS partition, but I guess I need to format it to become a ZFS partition, in which what is the point of the -t parameter?

 

[SirDice]

From gpart(8):

  Partition types are identified on disk by particular strings or magic
  values.  The gpart utility uses symbolic names for common partition types
  so the user does not need to know these values or other details of the
  partitioning scheme in question.  The gpart utility also allows the user
  to specify scheme-specific partition types for partition types that do
  not have symbolic names.

In short, the partition needs a specific identifier to specify the partition type. That's what the -t does.