A Note About Streaming; Rotation Schedule - HP BB118BV - StorageWorks Data Protector Express Package User's Manual & Technical Reference

Figure 135 Rotation Schedule
The selected rotation type depends on your business requirements for retaining data. A popular choice
is the GFS type (Grandfather-Father-Son), which allows you to set up a rotating schedule with different
retention policies for daily, weekly, monthly and annual backups.
GFS-30 requires 30 media sets. Note that a set may actually equate to one or more physical cartridges
— if it is necessary to span cartridges during a backup session, Data Protector Express does this
automatically.
Look at Interval Settings. This rotation type makes 12 sets available for daily backups, 8 sets for weekly
backup, 8 sets for monthly backup and 2 sets for yearly backup. What this means is that daily backup
cartridges are effectively retained for two weeks before they are overwritten; weekly backups are retained
for 2 months before they are overwritten, and so on. Simply click the cursor in a date in the calendar;
information about the set to which it belongs is shown in the information text below the calendar. Daily
backups always default to incremental; weekly, monthly and yearly default to full, (regardless of any
settings you made to the Backup and Write modes in the Job Options step of the wizard).
If this retention policy is over-cautious for your needs, simply select Custom as the Rotation type to
make the GFS-30 model editable. You can then change the number of sets and edit the write mode,
if required, by clicking on the appropriate interval button. For more information on media rotation,
see Media Rotation for Backup Jobs.

A Note About Streaming

A stream is a set of files to be backed up asynchronously to other streams. Data Protector Express
automatically enables multi-streaming within the software, providing up to eight concurrent data streams
per drive (depending on license of the edition) and streaming to multiple devices in parallel.
Streams are assigned to a device in a round robin method. If you have two streams and two devices,
Data Protector Express will use both devices in parallel. Data Protector Express uses self-tuning logic to
determine the most appropriate way of streaming data. For example, if you are backing up a C: and a
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User's Guide and Technical Reference