A customer has these servers in their IT environment.
.1 Exchange server
.6 SQL database servers
.5 file servers
.16 application servers
The customer is using an HP StoreOnce Backup System to back up their data. To achieve the
best deduplication ratio/performance compromise, how many virtual libraries should be created?

A.
1

B.
4

C.
5

D.
13

Explanation:
http://www.manualslib.com/manual/484560/Hewlett-Packard-D2d.html?page=7
Key factors for performance considerations with deduplication:
The inline nature of the deduplication process means that there will always be some performance

trade-off for the benefits of increased disk space utilization.
With each Virtual Library or NAS Share created there is an associated dedicated deduplication
store. If Globaldeduplication across all backups is required, this will only happen if a single virtual
library or NAS share is configured and all backups are sent to it.
The best deduplication ratio will be achieved by configuring a minimum number of libraries/shares.
Best performance will be gained by configuring a larger number of libraries/shares and optimising
for individual deduplication store complexity.
If servers with lots of similar data are to be backed up, a higher deduplication ratio can be
achieved by backing them all up to the same library/share. If servers contain dissimilar data types,
the best deduplication ratio/performance compromise will be achieved by grouping servers with
similar data types together into their own dedicated libraries/shares.
For example, a requirement to back up a set of exchange servers, SQL database servers, file
servers and application servers would be best served by creating four virtual libraries or NAS
shares; one for each server set.
When restoring data from a deduplicating device it must reconstruct the original un-deduplicated
data stream from all of the data chunks. This can result in lower performance than that of the
backup.
Full backup jobs will result in higher deduplication ratios and better restore performance (because
only one piece of media is needed for a full restore). Incremental and differential backups will not
deduplicate as well