Tape Rotation Example With Data Deduplication - HP D2D Manual

calculated and displayed on the Web Interface. This figure is dynamic, it updates automatically
as more data is written to the device.
Benefits of HP D2D deduplication
The main benefit is that it is possible to store more data and retain data for longer on each device.
The host using the device has access to a greater depth of historical data that would otherwise
have been archived offline.
Deduplication:
Provides efficient use of storage capacity by eliminating duplicate data
Reduces disk expenditures by reducing storage space required. You can get more backups
for each host on the same size of storage (HP StoreOnce device)
Prolongs disk data retention periods
Reduces the volume of data that must be sent across a WAN for remote backups, replication,
and disaster recovery – reducing both risk and operational costs
See Replication
Deduplication and compression
Compression is applied as part of deduplication. You can expect 1.6:1 compression even on the
first backup where no (or only a small amount of) deduplication can occur.

Tape rotation example with data deduplication

The two most significant factors affecting the deduplication ratio for backup are:
How long do you retain the data?
How much data changes between backups?
The following example shows projected savings for a 1 TB file server backup.
Retention policy
1 week, daily incrementals (5)
6 months, weekly fulls (25)
Data parameters
Data compression rate = 2:1
Daily change rate = 1% (10% of data in 10% of files)
Typical savings
The following table illustrates a reduction of approximately 1 1:1 in data stored. In practice,
assuming 1.25 TB is available for backup for this library, this means:
Without data deduplication: only two weeks of data retention is possible before it is necessary
to archive data offline.
With data deduplication: even after six months less than 1.25 TB of disk space has been used.
The following table illustrates how this affects the space required to store the data over 25 weeks.
The figures are used to generate the graph shown after the table.
16 Data deduplication
for more information about replication.