[Techtalk] xfs repartitioning

[Meryll Larkin]

Requesting guidance from someone with experience in LARGE partitions & xfs
file systems.

I would normally just try stuff, but this is a work computer and I don't
want to screw it up.  I also don't have anything that big at home for
experimentation.

I have a new server that was formatted with a completely empty xfs 80T file
system (CentOS 6).

The OS and boot partitions are on different HD completely.

I would like to reformat the 80T partition into 4 20T partitions - I need
guidance with this.  Anyone?

It is OK to completely destroy the 80T xfs partition first, but I need to
end up with 4 approximately 20 T  xfs partitions.

I am NOT a novice at all, but I am new at such large drives and xfs.  For
example, I thought that I could use familiar fdisk (wrong).

So here are the ways I've thought about it:

1.  Least favorite but most likely to work:  run CentOS 6 installer again
and reformat that one partition.  I have a vague idea about doing this, but
if someone has done it, pointers would be appreciated.
OR
2.  Use mkfs.xfs  but I am unsure about the syntax and don't know if I need
to first do something else like write zeros to the 80 T partition.  Or will
the -f (force) switch work?

This sentence is making me think I don't know what I'm doing (I hate
absolute sentences like this without qualifiers or explanations):
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/htm
l/Storage_Administration_Guide/ch-xfs.html
Note
After an XFS file system is created, its size cannot be reduced.

How about destroyed and remade into smaller partitions??

Meryll