Dell PowerVault DL2000 - Manual (Page 12)

ESG LAB VALIDATION
Dell PowerVault DL2000 Powered by CommVault
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Copyright  2008, The Enterprise Strategy Group, Inc. All Rights Reserved.
Deduplication
CommVault deduplication uses Single Instance Store (SIS) to reduce the capacity required to store backed up
file data. To illustrate the power of data deduplication technology, consider the example shown in Figure 10.
Redundant copies of files (Word, PowerPoint, Excel, and PDF) are included in a backup set. Data deduplication
examines the contents of files prior to storing them on disk or tape, recognizes and eliminates redundant copies,
and stores only the unique files.
FIGURE 10. COMMVAULT SINGLE INSTANCE STORE IN ACTION
Consider what happens when one copy of a PowerPoint file has been sent via e-mail to a number of team
members. Using file deduplication, CommVault recognizes the multiple copies as identical files and saves only
one copy. When one of the recipients makes changes and forwards the updated presentation to the team,
CommVault recognizes the identical copies of the updated presentation and saves only one additional copy.
Pointers are used to recreate the file when restored. The capacity required for many copies of the same
PowerPoint file, and the changed version, has been reduced significantly.
ESG Lab Testing
ESG Lab measured the capacity savings that can be achieved over a series of backup operations using the Dell
DL2000 Powered by CommVault appliance. The initial data set backed up was composed of 25 GB of randomly
generated file data.
A typical backup scenario was simulated using weekly full and daily incremental backups. A file creation utility
was used to grow the dataset by 1% daily to simulate changes between each backup. Synthetic full backups
were used in combination with CommVault SIS and compression.
ESG Lab measured the capacity consumed before and after running each backup. After four backup jobs had
been run, the capacity savings were measured at 85% and the rate for a 30 day retention policy was projected.