Today, I was installing the Oracle Database 11g R2 on a Solaris system, but it failed a prerequisite check during the installation – it did not have enough swap space available.  This particular system I had installed with ZFS.  Turns out that adding extra swap space on a ZFS system is slightly different than what you might be used to.  I am sure I am going to want to do this again some time, and I guess other folks will too, so here are the details.

Firstly, check where your swap file is (it will be a ZFS volume created during the Solaris installation):

bash-3.00# swap -l
swapfile             dev  swaplo blocks   free
/dev/zvol/dsk/rpool/swap 256,1      16 4194288 4194288

Then you will need to unmount it:

bash-3.00# swap -d /dev/zvol/dsk/rpool/swap

You should validate it is unmounted:

bash-3.00# swap -l
No swap devices configured

Then you can resize the ZFS volume (just give it the pool name and the volume name):

bash-3.00# zfs set volsize=16G rpool/swap

And then add it back into your swap space:

bash-3.00# swap -a /dev/zvol/dsk/rpool/swap

And now we see the swap space is back online and larger than before:

bash-3.00# swap -l
swapfile             dev  swaplo blocks   free
/dev/zvol/dsk/rpool/swap 256,1      16 33554416 33554416

Pretty easy once you know how!