Increase swap space?

Question

Hey,
Im using Solaris 10:
-bash-3.00$ cat /etc/release
                       Solaris 10 10/08 s10x_u6wos_07b X86
-bash-3.00$ uname -a
SunOS arrow 5.10 Generic_137138-09 i86pc i386 i86pcI've install the system using ZFS as the root filesystem:
bash-3.00# zfs list
NAME                          USED  AVAIL  REFER  MOUNTPOINT
rpool                        9.16G  20.1G  35.5K  /rpool
rpool/ROOT                   5.15G  20.1G    18K  legacy
rpool/ROOT/s10x_u6wos_07b    5.15G  20.1G  5.15G  /
rpool/dump                   1.00G  20.1G  1.00G  -
rpool/export                 1.34G  20.1G   300M  /export
rpool/export/home            1.05G  20.1G  1.05G  /export/home
rpool/swap                    790M  20.2G   730M  -
....So my question is, is there an easy way to increase the swap space in this configuration? If so, what is the command to do that?
The docs pointed me to this: http://docs.sun.com/app/docs/doc/819-5461/gazss?a=view, but I'm uncertain what properties to change. Am I on the right track or am I embarrassingly wrong here?

Answer 1

Be careful with changing a running system like that.. You changed the size of the pool but did you also make sure that the new swap space was initialized? iow; does "swap -l" really show more swap ? Its not the recommended way to do this, thats for sure..
So just for possible future reference..
The easiest approach (IMO) is to simply create a new swap filesystem, then tell the system to start using it, then turn off your old swapspace.. So something in the likes of...
zfs create -o volsize=2G rpool/swap2
swap -a /dev/zvol/dsk/rpool/swap2
swap -d /dev/zvol/dsk/rpool/swapAnd bingo.
Off course if you're a detail nut like myself then having a name "swap2" really won't do. So you could also simply use swap2 as temporary space and then resize your initial swap while also re-initializing the swapspace on it. I'm not too sure if that is also performed during boot.. So something like this:
zfs create -o volsize=2G rpool/swap2
swap -a /dev/zvol/dsk/rpool/swap2
swap -d /dev/zvol/dsk/rpool/swap
zfs set -o volsize=2G rpool/swap
swap -a /dev/zvol/dsk/rpool/swap
swap -d /dev/zvol/dsk/rpool/swap2Ofcourse all of this will put a little load on the disks, and if you're going to reboot anyway then it might make more sense to use a rescue cd of some sort and perform the change manually. However, I'd still advice you to double check since I'm not too sure about swap space getting re-initialized during boot. All the docs I've found regarding this subject all speak of re-creating the swap space itself as well.
Edit: And if you'd be a ZFS nut unlike myself you'd realize that its also perfectly possible to rename a dataset. So instead of creating a new dataset and moving the swap again it would be sufficient to simply rename it from swap2 to swap again. IMO this is really the easiest and safest way to resize swap. And it doesn't even require a reboot!