## "osname": Group of deployments that share /var

Each deployment is grouped in exactly one "osname". From above, you can see that an osname is physically represented in the `/ostree/deploy/`osname`` directory. For example, OSTree can allow parallel installing Debian in `/ostree/deploy/debian` and Red Hat Enterprise Linux in `/ostree/deploy/rhel` (subject to operating system support, present released versions of these operating systems may not support this).

Each osname has exactly one copy of the traditional Unix `/var`, stored physically in `/ostree/deploy/`osname`/var`. OSTree provides support tools for systemd to create a Linux bind mount that ensures the booted deployment sees the shared copy of `/var`.

OSTree does not touch the contents of `/var`. Operating system components such as daemon services are required to create any directories they require there at runtime (e.g. `/var/cache/`daemonname``), and to manage upgrading data formats inside those directories.