Replacing disks in MIRROR vdev, auto increase in size?

Hello TrueNAS people,

my mirrored vdev currently has 4tb, 8tb and a 12tb drive. I plan to take the 4tb drive offline and replace it with a 12tb drive. i currently can only connect up to 3 drives on my system because i dont have enough SATA power cables.

when i replace the 4tb drive with a 12tb drive, will the mirror automatically increase to 8tb in effective capacity? is this method advisable?

your advice is much appreciated.

You have to hit the Expand button in the GUI. Image shows button on right side

oo i see. thanks! i will do that!