Some notes on RootOnZFS article in wiki

Andriy Gapon avg at
Tue Dec 22 17:50:21 UTC 2009

on 22/12/2009 18:19 Scot Hetzel said the following:
> 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

Where swapon line? :-)
Okey, okey, it's good ti know that it works.

> 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.

Yeah, not nice.
I think that in OpenSolaris they do something special to zvol when it is
configured as a swap device, and then swapping code bypasses all the complex zfs
paths.  But I could very well be mistaken, I got this impression from a quick
cursory look over the source code.

Andriy Gapon

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