Expanding swap

Things change or underestimation may happen.
To increase the swap space backed by disk:
 

• Verify that disk-based swap is not in use (blocks == free):
   
  # swap -l
  swapfile                   dev  swaplo   blocks    free
  /dev/zvol/dsk/rpool/swap 256,1      16  8388592 8388592
   

• If not in use, simply resize the ZFS volume:
   
  # zfs set volsize=30G rpool/swap
   
• Or, if in use, create another swap device and add it to the VMM:
  (don't forget to adjust /etc/vfstab for persistence upon next reboots).
   
  # zfs create -V 26G -b $(pagesize) rpool/swap-x1
  # zfs set primarycache=metadata rpool/swap-x1
  # swap -a /dev/zvol/dsk/rpool/swap-x1
   
• Verify the new disk-based swap info:
   
  # swap -l
  swapfile                   dev  swaplo   blocks     free
  /dev/zvol/dsk/rpool/swap 256,1      16 62914544 62914544
   
   

Don't forget to adjust changes accordingly in /etc/vfstab.