Oddity here /dev/disk/by-id

[Harry Putnam]

Setup:
HDW: HP xw8600 (Old hardware circa 2008)
Fresh install of ubuntu 20.10

Running a fresh install of ubuntu-20.10.  Wanting to create
pool from the list at /dev/disk/by-id

I hoped to use the `long name' as we are always told to avoid using
the /dev/sdX names these days.

In previous installs on VBox vm; I did that with no problems

But this time ls -l shows me 2 names for everything (confusing):

... ata-ST320DM000-1BD14C_Z2AFV73D -> ../../sda
... ata-ST320DM000-1BD14C_Z2AFV73D-part1 -> ../../sda1
... ata-ST320DM000-1BD14C_Z2AFV73D-part2 -> ../../sda2
... ata-ST320DM000-1BD14C_Z2AFV73D-part3 -> ../../sda3
... ata-ST320DM000-1BD14C_Z2AFV73D-part4 -> ../../sda4
... ata-ST320DM000-1BD14C_Z2AFV73D-part5 -> ../../sda5
... ata-ST320DM000-1BD14C_Z6E049AD -> ../../sdb
... ata-WDC_WD1003FZEX-00MK2A0_WD-WCC3F5763895 -> ../../sdc
... ata-WDC_WD1003FZEX-00MK2A0_WD-WCC3F5798727 -> ../../sdd

    (spcs put here by author)

... wwn-0x5000c5003f34c76d -> ../../sda
... wwn-0x5000c5003f34c76d-part1 -> ../../sda1
... wwn-0x5000c5003f34c76d-part2 -> ../../sda2
... wwn-0x5000c5003f34c76d-part3 -> ../../sda3
... wwn-0x5000c5003f34c76d-part4 -> ../../sda4
... wwn-0x5000c5003f34c76d-part5 -> ../../sda5
... wwn-0x5000c5006631d9de -> ../../sdb
... wwn-0x50014ee20a4bd1fc -> ../../sdd
... wwn-0x50014ee2b4f6e404 -> ../../sdc

I googled up several meanings of the prefix `wwn'. It seemed like the
most common use was `WorlWideName'. Not sure if that is what is means here.

But the more confusing thing is that every one of my 4 disks and the
partitions on /dev/sda are given twice... each time with a different
name. 

So to create a 2 disk mirror pool I would nomally:

   zpool POOL mirror LONGNAME1 LONGNAME2

So what is the deal here?