6 Scheduling, Rotations, and Media Management
Ensuring that you have all the files needed to restore your system is a complex task. Typically, it is not practical — from either a time or a media perspective — to create a full backup every day. The solution involves running different types of jobs (full, incremental, differential or copy) on predefined schedule intervals using predefined numbers of media sets that get reused over time. The process of reusing media is referred to as media rotation. The media rotation type determines how and when each media set is used, how long it is retained once it contains data, and the granularity of your backup history.
A rotation defines the times it will run (see “Intervals”) and how many sets it will use (see “Media Sets”). When a job is configured to use a rotation in its schedule, the rotation set folders are created immediately. This allows you to see what media sets the job will be requesting. If the rotation type is changed, the set folders are updated to reflect the new rotation type. When the job runs, it will look for media with specific names in specific folders. If it does not find the precise media it is looking for, it will format any available media according to the auto format rules or will prompt you to insert media into your device before it continues. When the number of rotation runs has been reached, the next backup run will select the oldest set in the interval to overwrite.
Data Protector Express provides several built in media rotation types. In many cases, the name of the rotation type indicates the number media sets used in the rotation. For example, the Simple 4 rotation type will use four media sets (at least four individual tapes) to complete the rotation. The media set names can be based either on the scheduled interval or on the type of fixed rotation.
TIP: HP recommends that you let Data Protector Express format your media. In most cases there is never a need to
The Jobs and Media view displays jobs, media and folders in the Data Protector Express catalog. When you first open the Jobs and Media view you will see a listing of your Home folder. Your Home folder is where Data Protector Express stores the jobs you create and the media created by those jobs.
CAUTION: When you delete media, Data Protector Express deletes information about that media from its catalog. This includes any versions of files stored on that tape, which are also deleted from the catalog. Deleting media does not physically erase the media. The media remains unchanged; only the catalog is changed. You can still import that tape to another catalog or, if necessary, back into the original catalog.
TIP: When viewing the Jobs and Media view, clicking the Folders command will display a tree view of the Home folder hierarch that can be helpful in understanding the organization of media within jobs.
Backup Schedule Considerations
Data Protector Express lets you set up jobs that run automatically on regular schedules. To determine which type of backup job you should create, ask yourself these questions:
•How many days of data can you afford to lose?
•How large will a full backup job be?
•How much does your data change on a day to day basis?
•How many media does your budget allow?
•How much data can the backup media hold?
Backup Schedule Considerations 35