Usage and Implementation Overview
Holland is built around the concept of plugins, though for the end user, most of these plugins will be in the form of backup providers and their helper plugins. These are configured by way of a backup-set which defines the characteristics of a particular backup.
Provider plugins provide a backup service for use in a backup set. They are the interface between Holland and the method of backing up data.
As Holland is a framework, it can actually backup most anything as long as there is a provider plugin for it. The idea is to present an easy to use and clear method of backing up and restoring backups no matter the source.
A backup-set is compromised of global, provider, and helper plugin configuration options which make up a particular backup. These options are stored in a simple INI-based configuration file. The name of the configuration file corresponds to the name of the backup set.
For instance, once might want to backup a handful of MySQL databases using some specific mysqldump settings; while backing up another set of MySQL databases using different settings. To do this, one might create two backups sets for each scenario.
Most plugins come with a set of defaults such that only values that need to be overridden need to be specified in a backup-set if desired. Such defaults can be modified on a global basis by editing the global provider configuration files (see :ref:`overview-providers`).
Backups are of course the end product of the whole exercise. Holland stores
these under the
backup_direcotry defined in the main
configuration file. The default location is usually
Under this directory there is a sub-directory for individual backup-sets.
Under those directories are the actual backup directories. The name of each
backup directory is the timestamp of when it was run. As of Holland 1.0.8
or newer, there are also
oldest directories which,
perhaps unsurprisingly, correspond to the newest and oldest backup.
As implied, there can be multiple backups under a backup-set. The scheduling
of running backups is up to you. Holland does not care how often backups are
run - it only cares about how many backups to keep. This, with the help of
cron, one can be fairly flexible about the scheduling and
frequency of backups.