When will zfs 0.7 be available

And I'm wondering when this will be included in ubuntu

When it is considered stable and zfs 0.7 is not stable yet.

I have not found a ppa for 0.7

But there is one. Personal archive to add 0.7 to your system ...

sudo add-apt-repository ppa:zfs-native/daily
sudo apt-get update

And yes: this is experimental. So prepare for failure, like a wiped disk.

See their launchpad page on comments on this. Last update was 4 weeks ago so someone is waiting on someone ;)

Another method of adding this ...

deb http://ppa.launchpad.net/zfs-native/daily/ubuntu trusty main 
deb-src http://ppa.launchpad.net/zfs-native/daily/ubuntu trusty main 

Leave the "trusty" as is and it will install. Mileage may vary though as it was not intended for other releases.

Stable version should be used (and that is 0.6.5). Personal archive:

sudo add-apt-repository ppa:zfs-native/stable
sudo apt-get update

And in case anyone wants to know what zfs is: wikipedia on zfs ...

ZFS is a combined file system and logical volume manager designed by Sun Microsystems. The features of ZFS include protection against data corruption, support for high storage capacities, efficient data compression, integration of the concepts of filesystem and volume management, snapshots and copy-on-write clones, continuous integrity checking and automatic repair, RAID-Z and native NFSv4 ACLs.

and this specifically on Ubuntu:

Ubuntu integration

The question of the CDDL license's compatibility with the GPL license resurfaced in 2015, when the Linux distribution Ubuntu announced that it intended to make precompiled OpenZFS binary kernel modules available to end-users directly from the distribution's official package repositories. In 2016, Ubuntu announced that a legal review resulted in the conclusion that providing support for ZFS via a binary kernel module was not in violation of the provisions of the GPL license. Others followed Ubuntu's conclusion, while the FSF and SFC reiterated their opposing view.

Ubuntu 16.04 LTS ("Xenial Xerus"), released on April 21, 2016, allows the user to install the OpenZFS binary packages directly from the Ubuntu software repositories. As of April 2017, no legal challenge has been brought against Canonical regarding the distribution of these packages.

The current beta of Ubuntu 18.04 is shipping with ZoL 0.7.5: https://packages.ubuntu.com/bionic/zfs-dkms