Yup you are correct. I did use the parity drive before i added it and did not pre-clear it.
parity (sdj)
root@NAS:~# fdisk -l /dev/sdj
Disk /dev/sdj: 14.55 TiB, 16000900661248 bytes, 31251759104 sectors
Disk model: ST16000NE000-2RW
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 969E3CEE-0602-3C4B-8C24-CCB4AF681B02
Device Start End Sectors Size Type
/dev/sdj1 2048 31251759070 31251757023 14.6T Linux filesystem
Parity 2 (sdk)
root@NAS:~# fdisk -l /dev/sdk
Disk /dev/sdk: 14.55 TiB, 16000900661248 bytes, 31251759104 sectors
Disk model: ST16000NE000-2RW
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 0373AE92-FB71-44E1-84F2-5740B340029F
Device Start End Sectors Size Type
/dev/sdk1 64 31251759070 31251759007 14.6T Linux filesystem
drive I'm trying to add (sdd)
root@NAS:~# fdisk -l /dev/sdd
Disk /dev/sdd: 14.55 TiB, 16000900661248 bytes, 31251759104 sectors
Disk model: ST16000NE000-2RW
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0x00000000
Device Boot Start End Sectors Size Id Type
/dev/sdd1 1 4294967295 4294967295 2T 0 Empty
Partition 1 does not start on physical sector boundary.
So it looks like I need to take this new drive and make it the Parity drive. correct?