Kernun UTM is able to use one or two disk devices. Each disk device is either a physical disk, or a logical disk provided by a hardware RAID. The disk space is divided into three system partitions, one data partition, and swap space. In single disk configurations, all four partitions and the swap space are located on the single disk. In configuration with two disks, the system partitions are on one disk, whereas the data partition and the swap space on the other.
Each system partition may contain a complete Kernun UTM installation including the operating system, application proxies, administrative tools, and additional software. The data partition contains logs, statistics, installation images, and backups. The contents of the data partition are shared by all Kernun UTM installations in the system partitions.
The use of three system partitions minimizes downtimes during reinstallations and upgrades. While the system started from one system partition is fully operational, it is possible to install another version in the second partition. Then the new version can be started by a simple reboot. It is always possible to revert to the old version if anything goes wrong with the new one. The next upgrade will be installed in the first partition while running the system from the second one. In this way, two system partitions can be alternated for subsequent upgrades. The third system partition can be used in a similar fashion, so that two previous versions are always available, or for an alternative installation, e.g. when testing a completely new configuration.
When a system partition is booted, it becomes the root file system.
The other system partitions can be mounted to the directories
/1, /2, and
/3. There are lines in /etc/fstab
prepared for this, but the partitions are not mounted automatically.
The data partition is always mounted as /data
automatically. It contains the following directories:
/data/backupSystem backups are stored here. They can be used for restoration or copied to another medium.
/data/distThis is where Kernun UTM installation images are kept. During each installation, the installed image is stored here for future reuse.
/data/logThis directory contains log files. The log directory
/var/log from all system partitions is symlinked
here.
/data/rrdThis directory contains database files used to store system data for system performance monitoring, as well as graphs generated from this data.
/data/statisticsReports with detailed statistics of proxy operation are stored in this directory.
The standard disk space layout is created during the first installation of Kernun UTM on a new computer. It can be re-created or modified using the installer booted from the installation medium, but such action deletes all data on the system and data disks.
It is strongly recommended not to modify the standard disk layout, as many parts of Kernun UTM depend on it. You may add additional file systems and directories, but do not delete or move any file system or directory created by the Kernun UTM installer.