Replacing disks in the Thecus ZFS Nas

Expanding on my previous post about the Thecus, I'm finally at the stage where I'm going to be swapping out some of the disks. To start with, I had left an empty slot in the chassis, so I've thrown a new 4TB drive in there (/dev/sdi)

I then want to replace one of my existing smaller disks (I picked /dev/sdd, which was a 500gb drive) with the new one.

ZFS loves this sort of stuff.

root@thecus:~# zpool status
  pool: n8800pool
 state: ONLINE
  scan: scrub repaired 0 in 5h6m with 0 errors on Sun Nov 13 05:30:41 2016
config:

        NAME        STATE     READ WRITE CKSUM
        n8800pool   ONLINE       0     0     0
          raidz2-0  ONLINE       0     0     0
            sdb     ONLINE       0     0     0
            sdc     ONLINE       0     0     0
            sdd     ONLINE       0     0     0
            sde     ONLINE       0     0     0
            sdf     ONLINE       0     0     0
            sdg     ONLINE       0     0     0
            sdh     ONLINE       0     0     0

errors: No known data errors
root@thecus:~# zpool replace n8800pool sdd sdi
invalid vdev specification
use '-f' to override the following errors:
/dev/sdi does not contain an EFI label but it may contain partition
information in the MBR.
root@thecus:~# zpool replace -f n8800pool sdd sdi
root@thecus:~# zpool status
  pool: n8800pool
 state: ONLINE
status: One or more devices is currently being resilvered.  The pool will
        continue to function, possibly in a degraded state.
action: Wait for the resilver to complete.
  scan: resilver in progress since Tue Dec  6 12:27:22 2016
    248M scanned out of 1.94T at 4.50M/s, 125h42m to go
    35.1M resilvered, 0.01% done
config:

        NAME             STATE     READ WRITE CKSUM
        n8800pool        ONLINE       0     0     0
          raidz2-0       ONLINE       0     0     0
            sdb          ONLINE       0     0     0
            sdc          ONLINE       0     0     0
            replacing-2  ONLINE       0     0     0
              sdd        ONLINE       0     0     0
              sdi        ONLINE       0     0     0  (resilvering)
            sde          ONLINE       0     0     0
            sdf          ONLINE       0     0     0
            sdg          ONLINE       0     0     0
            sdh          ONLINE       0     0     0

errors: No known data errors
root@thecus:~#

Now after performing this for every 500gb device (sigh) you just need to expand them with 'zpool online -e sdi' or whatever the new device name is.