OpenZFS on OS X

One disk in another 4-disk raidz I admin is showing FAILING for the SMART status.
What is the best way to go about replacing this disk before it bellies up entirely? Using the zpool replace command? Is there a documented sequence I can read to prevent me making a FU using my basic knowledge of zpool commands.

Thanks Brendon. Odd thing is the Mac DU shows SMART status as verified while another non-OS X SMART utility shows it as failing. Better safe than sorry. I don't really understand that long number in that wiki reference and where it comes from because I don't see it anywhere and none of my disks are degraded (yet).
Still here goes.
Nope, that does not work—presumably because the disk is not faulted and is still online. I'll do some more reading.
NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
media-8B686CD3-7C6D-47EC-B1B5-AC21745FA7AE ONLINE 0 0 0
media-4267E549-8CFF-4EA0-901D-BB7CC9B7AF09 ONLINE 0 0 0
media-F44E2E6C-215A-4D5D-949D-3B47749C91CC ONLINE 0 0 0
media-CA94C25F-3C7B-4D73-A427-B394F7C6A245 ONLINE 0 0 0

errors: No known data errors
Mac-Pro:~ roberthancock$ sudo gpt destroy disk1
Password:
gpt destroy: unable to open device 'disk1': Resource busy
Mac-Pro:~ roberthancock$

OK done more reading at Oracle and think I understand but one problem, in the list of four disks labelled media-....., how do I find which is disk1 (the disk reported as having failing SMART)?

You are seeing the Invariant Disks names. They are located in /var/run/disk. The names are softlinks to /dev/diskX nodes. Use ls -l to see what is what.

Cheers
Brendon

nekton34 wrote:OK done more reading at Oracle and think I understand but one problem, in the list of four disks labelled media-....., how do I find which is disk1 (the disk reported as having failing SMART)?