How to change the size of swap and dump area in ZFS after installation

You can reset the volsize property of the dump device after a system is installed. For example:

# zfs set volsize=2G rpool/dump
# zfs get volsize rpool/dump

NAME        PROPERTY VALUE       SOURCE
rpool/dump volsize   2G          -

If the current swap area is not in use, you can resize the size of the current swap volume, but you must reboot the system to see the increased swap space size.

# zfs get volsize rpool/swap

NAME        PROPERTY VALUE    SOURCE
rpool/swap volsize   4G       local
# zfs set volsize=8g rpool/swap
# zfs get volsize rpool/swap

NAME        PROPERTY VALUE    SOURCE
rpool/swap volsize   8G       local

# init 6

Reference

[1] http://docs.oracle.com/cd/E26505_01/html/E37384/ggrln.html