Some notes on RootOnZFS article in wiki

Scot Hetzel swhetzel at
Tue Dec 22 16:19:52 UTC 2009

On 12/22/09, Andriy Gapon <avg at> wrote:
> on 22/12/2009 13:02 krad said the following:
> >
>  > Are there still issues with using zvols for swap? If not you don't need a
>  > slice for swap and can get rid of gmirror entirely.
> Is this supported at all _on FreeBSD_?
>  Even, if yes, one drawback is that you wouldn't be able to use zvol swap as a dump
>  device.
FreeBSD does support zvols as swap:

zfs create -V 2gb zroot/swap
zfs set org.freebsd:swap=on zroot/swap
zfs set checksum=off zroot/swap

Another drawback to using zfs swap is that zfs requires RAM for it's
arc cache and if your system is low on RAM, the system may stop
responding even if you still have space in the zfs swap volume.


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