Data De-duplication and Disk-to-Disk Backup Systems

ESG Report
Data De-Duplication and D2D Backup Systems
duplication process immediately after data is written to the backup target may shorten the length of the
de-duplication process, but will also affect the data ingest rate.
4. Does the D2D backup solution support de-duplicated remote replication?
End-users may wish to implement remote replication for disaster recovery, remote backup and remote
vaulting. The combination of data de-duplication and remote replication offers a great deal of value by
reducing bandwidth as dramatically as it reduces storage capacity. In many cases, data de-duplication
can enable disaster recovery and remote backup in terms of meeting backup windows and budget
constraints.
Some data de-duplication solutions support multi-site remote replication. If this is a requirement, find
out if the vendors you are considering support multi-site. The next question to ask is whether they
support data de-duplication across the entire environment. For example, if there is duplicate data in
five different sites, will it store only one copy at the target site? And will it make sure that no duplicate
data will be sent over the WAN? Supporting multi-site data de-duplication raises the level of capacity
reduction efficiency.
5. Will de-duplication processes affect my disaster recovery windows?
While much of the focus in the industry around data de-duplication is focused on reduction ratios and
performance capacity trade-offs, it is also important to consider the effect data de-duplication may have
on disaster recovery windows. This refers to the time it takes from the start of the backup process to the
point where DR copies are made and moved off-site. The length of this process— from start to finish—
depends on a number of variables, including the data de-duplication approach, the speed of the deduplication
architecture, the DR process (is the data being written/exported to tape or de-duplicated
and then replicated over a WAN to a remote facility), etc. It is important to consider the lag time from
initiation of backup to when the image is complete at the DR site. If this timeframe is greater than 24
hours, that image may miss too much new data to meet the DR objectives of your deployment. Make
sure you are meeting the Recovery Point Objectives (RPO) you have in mind for DR.
6. Is the D2D solution easy to implement?
One of the compelling things about data de-duplication is that it is easy. Or at least it should be. Users
shouldn’t have to perform cumbersome, complex and time consuming tasks to get up and running in
order to derive value from their solutions. Data de-duplication should be invisible to the backup and
recovery process.
Purpose-built D2D backup appliances also offer a level of transparency, acting as a total solution that
doesn’t require disk storage management functions. VTL solutions are typically associated with ease
of implementation, since they emulate tape libraries. Certainly, they provide a great deal of value
compared to just using a general purpose storage system, which often is complex to manage and
requires storage experts. The backup administrator doesn’t want to manage RAID groups, LUNs and
volumes.
7. What is the system impact of performance?
More controllers? More disk? What ratio of each? This matters for cost and system management
reasons.
8. How does the D2D backup solution protect itself from data loss and corruption?
It is important to understand how “bullet proof” the D2D backup solution is. Find out what technologies
it has to ensure data integrity and protection against system failures. While this is always important, it
is an even bigger consideration in data protection with de-duplication. With D2D backup solutions that
Enterprise Strategy Group Page 7