CDP vendors and product selection
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Software CDP products are more plentiful and diverse, making the
product choice more difficult. Symantec BackupExec 10d is a
true-CDP product, journaling and indexing data as it comes in.
According to Goodwin, BackupExec is optimised for restore
operations through a Google-like interface that allows users to
look for and recover lost files. BackupExec10d also integrates with
BackupExec backup software and allows for integrated operations
between the backup and CDP catalogs. However, 10d is very sensitive
to excess data (aka data bombs). "If it's just getting flooded with
data, it may need to suspend journaling until the data bomb is
over," he says. "It's not going to 'lose' data, but you may
[temporarily] loose the recovery point granularity in the event of
a data bomb."
BackupExec stands in stark contrast to near-CDP products, like
Microsoft DPM, which behaves like a snapshot tool offering limited
granularity. However, Goodwin points out that DPM is well optimised
for backup tasks, is easy to implement, and its snapshot nature
makes it virtually immune to data bombs. "DPM is not going to have
a problem dealing with those scenarios," he says. "But its recovery
point is no better than one hour."
Other CDP products include offerings from Atempo Inc., IBM
Tivoli, Topio Inc., and FilesX Inc. Atempo's LiveBackup handles
transparent CDP for Windows desktop and laptop PCs in the global
enterprise. Files are sent remotely to LiveBackup servers across
wide area networks (WAN), local area network (LAN) or Internet
connections. The Topio Data Protection Suite (TDPS) software has
been gaining popularity for its ability to replicate and recover
enterprise data across a variety of locations, platforms and
storage. Xpress Restore software from FilesX touts bare-metal
recovery capability for Exchange, SQL and file servers.
In terms of application-specific CDP products, Atempo supports
Microsoft Exchange with its LiveServ for Exchange Servers product.
Other application-specific CDP software products include NearPoint
for Exchange from Mimosa Systems, TimeData for SQL, TimeData for
Windows Fileserver and TimeData for Exchange from TimeSpring
Software. The Enterprise Rewinder from CA can configure, monitor,
manage and perform recovery on all of your Exchange, SQL, Oracle,
file and other application servers from a single console.
Selecting the right product
Ultimately, an organisation must consider the need for CDP very
carefully before making a purchase decision. The goal of CDP is to
minimise recovery points and recovery times, but if those
objectives are met with more conventional technologies (e.g.,
snapshots), CDP may not provide optimum value to an organisation.
Analysts suggest the following points that will help you identify
the best product for your own production environment.
Determine the CDP granularity. True-CDP products
typically journal storage activity down to individual writes, while
near-CDP products behave like more conventional snapshot systems.
Both approaches clearly provide value, but it's important to
evaluate the behavior of each CDP offering against your specific
data protection needs. Organisations with extremely tight RPOs may
require true-CDP platforms. Otherwise, an enterprise may opt for
less expensive and more readily available snapshot or near-CDP
products.
Weigh file-based vs. block-based CDP. File-based
applications are often best served by a file-based CDP product,
which can restore individual files on demand and is often quicker
for smaller or limited restorations. By comparison, block-based
applications often run on raw volumes for improved performance.
Block-based CDP products operate at a lower level and can handle
all types of applications, but recovery takes a bit longer since
the entire volume must be restored before recovering particular
files.
Consider the application(s) that CDP is intended to
protect. CDP is typically implemented to support specific
applications in the enterprise, such as email or database servers.
Pick a CDP product that supports your mission-critical
applications, as well as any related applications. As an example, a
CDP product intended for Oracle should also support related
applications, like
enterprise resource planning (ERP), finance
or other applications that use the database.
Evaluate the management overhead. Expect to invest
significant time to plan, integrate, configure, tune and optimise a
CDP platform. But once the product is operating, it should run
almost unattended. At most, it should demand no more management
time than other snapshot or replication platforms. "The more time
you have to spend with it, the less value that [CDP] solution has,"
Schuls says. "If you're buying a solution where you have to put
more manpower around it, that tells me you have the wrong
solution." Pilot testing can help to identify management
requirements.
Test and evaluate the product in-house. CDP technology
should be tested thoroughly before making a purchase decision.
Evaluate the interoperability with existing storage and other
elements in your infrastructure. Examine the impact of scripts and
drivers (agents) on servers. Test restorations and ensure that key
applications will continue to run without disruption -- especially
in a busy transactional environment where content may be buffered
in memory.
Best practices for implementation
At this point, it's difficult to identify a complete set of best
practices for CDP -- there just aren't enough deployments yet for
best practices to fully solidify. "CDP is such a new technology
that best practices are still not quite prevalent," says Arun
Taneja, consulting analyst and founder of the Taneja Group in
Hopkinton, Mass, noting that Mimosa and other application-focused
CDP products do tout a more established user base. Still, some
well-grounded policies can help smooth common CDP implementation
issues.
Don't use CDP to replace other backup or data protection
plans. Just as tape, D2D, VTL, replication and snapshots fill
specific storage roles, CDP fills a unique need in the overall data
protection scheme. While it might be technically feasible to use
CDP in place of other storage platforms, analysts are unanimously
against the idea. "The bigger question is where does this [CDP] fit
into the data protection continuum, and how does it improve your
process?" Goodwin says.
Ensure adequate network bandwidth to move data. Data
protection technologies require network bandwidth to move data from
one place to another. With a CDP deployment, Goodwin suggests
maintaining at least 20% additional space and bandwidth capacity to
accommodate an unexpected restore job. Otherwise, network
performance may suffer (possibly compromising service levels)
during restorations.
Start small, build out and tweak as necessary. As a
relatively new technology, it's difficult to predict the impact of
CDP on existing infrastructures, so users typically opt to start by
deploying CDP to protect a single noncritical application (or a
critical application in parallel with existing protection
initiatives, like snapshots). Schulz points to his own experience
with CDP problems. "What caught my attention was the extra traffic
it [CDP] was putting on my network, and extra traffic it was
causing to some storage," he says. "All of a sudden my backup jobs
were running a little longer because they were picking up the CDP
caches that I hadn't thought about excluding." The goal is to
evaluate the behaviors and limitations of CDP -- gaining experience
with the CDP product before extending the deployment.
Remember to implement security measures. CDP allows for
fast restoration, but understand who is authorised to restore data,
when restores are permitted and where restorations can occur. Be
sure that users can only restore data that they are responsible for
and authorised to handle. Otherwise, CDP's flexibility may become a
serious security threat to the organisation.
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