White Papers

99 Setting Up the Dell™ DR Series System on Symantec™ Backup Exec™ | April 2015
In the previous example at the end of the 5-week cycle the 1
st
week retires and frees up media to be reused
or recycled which once processed will allow the DR to reclaim the physical space associated with the
virtual media. Since the smallest data set footprint resulting from the change rate is 2TB in each
incremental iteration we create our media at 800GB increments and add as we grow. For this example the
initial Virtual Tape Library would be created with 152
( 121TB divided by 800GB ) pieces of media at 800GB
for each piece media.
20TB Total initial footprint with a 10% change rate
Pre-Deduplication
W
ee
k
Logical
Size
Logical
Full Metrics
10% Change Rate
Logical
Incremental Metrics
1
24.2TB
20TB
2TB
2
24.2TB 20TB 2TB
3
24.2TB 20TB 2TB
4
24.2TB
20TB
2TB
5
24.2TB 20TB 2TB
Total
121TB
C.2.4 Media retention and grouping
Due to the nature of Virtual Tape Libraries media must be managed in order to insure that physical capacity
is reclaimed in an orderly fashion to avoid running out of space and disrupting operations. Media must be
grouped within the data management application, such as NetVault Backup, in a way that full data sets are
targeted to separate media as incremental data and they in turn are grouped by data sets that expire within
the same period or that share the same recovery point
objective. This ensures that media can be reused
effectively so that when full all incremental data expire the logical space can be reconciled thus enabling
the physical space to be reclaimed.
C.2.5 VTL media count guidelines
Type Capacity Max number of Tapes supported
LTO-4 800GiB 2000
LTO-3 400GiB 4000