Double-Take Software, Inc.
    Published: January 2008

    Customers and coworkers expect that you are accessible and responsive, regardless of the
    infrastructure and technologies you have in place. Wireless email might arguably be the greatest
    enhancement to employee productivity since the cell phone, enabling employees to keep up with
    email when traveling. With its prevalent use today, the expectation is that users will have
    anywhere/anytime access to messaging systems such as Microsoft Exchange and Lotus Notes®.
    It is more important than ever to ensure that messaging systems and wireless email services are
    protected from disasters and other outages.


Your entire team's productivity has been increased with BlackBerry™ handhelds - but what if the server and software that powers these
devices goes down?

Wireless email might arguably be the greatest enhancement to employee productivity and flexibility since the cell phone. It enables employees
to keep up with email when traveling by allowing them to remain connected to coworkers and customers as if they were sitting in their
offices. A 2006 Gartner report states that there are approximately 12 million wireless email users worldwide, but predicts that by 2016, all
mobile phones will have wireless email functions - making all 2.4 billion phone users candidates for wireless email use.1

However, as is the case with most technologies that are designed to help companies work smarter and faster, there are new issues and
concerns to consider. For example, information on mobile devices can be erased if the device is damaged (or lost). Depending on the industry,
the data on a BlackBerry may be subject to corporate backup policies and should not be left in the hands of the user.2

Additionally, now that customers and employees expect to have anywhere /anytime email access, it is crucial that the system is protected from
failures and other outages. As employees have become dependent on this new freedom, BlackBerry Enterprise Server and handheld
deployments have gone from being convenient to being expected.

In the event of a system outage, it's not likely that users will even know that the communication link is down. Employees may make critical
decisions based on a lack of information and your customers and partners may simply assume your company is unresponsive.

How do you protect the investment you have made in these mobile systems and ensure that BES is always available?

1 Dulaney, Ken. "New BlackBerry Device Portends Change in Direction for RIM." Gartner. 11 September 2006
2 Troni, Federica. "How to Support PDAs and Smartphones in Business." Gartner. 28 August 2006


BlackBerry Enterprise Server - An Overview
In order to implement a plan for protecting and backing up BlackBerry handhelds, it's important to understand how the BES solution works
within an existing email environment.

Traditional corporate email is based on one or more mail servers, each running an email application such as Microsoft Exchange or Lotus
Notes. These mail servers may serve multiple roles in the messaging system including acting as a mailbox server, routing internal messages,
providing web-based access or acting as an internet mail gateway. The internet mail gateway sends and receives mail from the internet
allowing email communications with others outside of the company. For employees, accessing the email server is as simple as pointing a web
browser or desktop mail client to their specific mail server. The productivity tax with this scenario is it requires the user to be connected to the
corporate network, which isn't always possible when traveling.

In this situation, email piles up until the user can get to their computer. The success RIM has found in designing and marketing their
BlackBerry handhelds and server software is that they both allow companies to cut these ties and extend corporate email capabilities to any
location that provides a cellular connection. By providing microcomputer devices (complete with full keyboards and send and receive
capabilities), users can be connected to the email server from just about anywhere. When using a BlackBerry handheld, email goes from the
handheld to the BES, which in turn sends the email to the mail server for normal processing.

                                  Figure 1: How Blackberry works within the existing email solution


Wireless email Protection Considerations
Implementing a Disaster Recovery (DR) plan means changes to corporate culture, additional processes, technologies, documentation,
identifying key personnel and their emergency roles, and provisioning an alternate infrastructure. End users may think of a disaster as
something dramatic, like an office fire or flood. However, IT professionals may consider a disaster to be something as simple as a blown
power supply or a server shutdown.

When planning for protection against a disaster, it is important to understand the level of protection necessary for your business, and for each
of the scenarios outlined above as each has its own specific needs. For instance, while having a local mirrored copy (via hardware RAID) of
email data would help to recover from a local disk failure, it would not help in the event of an outage that affects the entire building or even
the region. Replicating or backing up data offsite would address this concern. However, it may not be practical or efficient to recover a local
disk failure from a set of data that is hundreds or thousands of miles away. Often it is important to have multiple levels of protection to
ensure the most rapid recovery from an outage.

When choosing a solution, it is important to consider not just the actual technology but also the reputation and the level of experience the
vendor has in implementing such solutions, as they will often be the ones assisting you to ensure that the right solution is deployed and the
implementation is successful. Implementing the wrong solution can be as harmful to your business as not implementing any solution.

While different options and solutions can provide a very highly protected email system, it is important to weigh the different variables of each
solution (cost, complexity, results, etc.) against overall business needs.

A Holistic View of Wireless email Services
While the entire IT group may look at individual components as being "up" or "down", users and customers only understand whether email
is working or not. This includes everything from the wireless handheld, to the BES, to the email server. From their perspective, the entire email
system is down - even if they just can't access email from one of their many different client interfaces.

Since BES relies on the data that resides on the email server (email messages, addresses, public folders, etc), part of ensuring the availability
of wireless email access is the absolute requirement to provide protection for the email server itself. Without an Exchange or Lotus Notes
system to interact with, BlackBerry Enterprise Server will not function. Regardless of specific goals, all availability efforts start by ensuring the
resilience and availability of all email data. Having a readily available copy of this data is the first step in protecting these applications.

In the past, the two most common options available for data protection were tape backup and hardware disk mirroring. However, these two
options have some major shortcomings that may result in less-than-satisfactory results when deployed as part of a high availability solution.

Because every business has its own service levels and business needs, each will have unique requirements for the level of data protection
needed, which will often result in different implementations of the selected technologies, or possibly even alternate technologies. What's good
for one company may not be appropriate for another. Your specific business needs will determine what solutions are right for you.

Tape Backup
With tape, backups typically are performed once per day with cartridges being shipped to a storage facility or vaulting service. One of the
major issues with tape backup is that it leaves large windows of unprotected data in between backups. This can leave up to 24 hours of lost
data should a recovery from tape be necessary - as a failure during the day would result in lost data back to the point of the last successful
backup. Another major concern with tape backup is that recovery time is often well beyond many businesses' recovery time objectives. While
tape backups are still necessary for long-term archival purposes, this solution is often inadequate as a high availability and disaster recovery


Hardware Disk Mirroring
Hardware disk mirroring, when done synchronously, can provide zero data loss in the event of a hardware failure, as data is mirrored to a
secondary storage device. However, the cost often exceeds many IT budgets. Many disk-mirroring solutions require identical hardware systems,
impose performance overhead due to the "round-trip delay" between systems, and require significant bandwidth since full disk blocks
(including unused blocks) have to be mirrored. Due to the technical nature of these solutions, both copies of data are typically in the same
power grid, weather zone and municipality due to inherent distance limitations between devices. In fact, some industries have started
mandating that synchronous mirroring must be supplemented in order to meet disaster recovery and data protection requirements. Even if
cost were not an issue, it is likely that synchronous mirroring would not provide adequate protection and availability of the email system.

So then, if you conclude that "tape does not provide fast enough recovery and is not routine enough for adequate data protection" but
"synchronous is too expensive and doesn't provide enough distance" what other option is there? Asynchronous host-based replication.

Host-Based Replication
Enterprise-class host-based replication solutions offer the best of many worlds, including heterogeneous hardware and storage support,
unlimited distance replication, real-time protection, and many options for customization to meet the varying needs of businesses in any
market. Typically, host-based replication solutions use existing IP-based networks, eliminating the need for proprietary or dedicated networks
while allowing for virtually unlimited distances in which data can be replicated, thus providing an excellent disaster recovery solution for all
critical data.

As the leader in host-based replication solutions, Double-Take Software has been protecting email and data for over 10 years, with proven
skills and experience to help ensure success in implementing business continuity solutions.


Double-Take: Proven Protection
Today, Double-Take is the most relied-upon solution for real-time replication of critical
data and automated failover for application availability. Double-Take is Microsoft®
Windows® 2000 and 2003 certified at all levels, one of the few replication products
to have achieved this level of certification. It delivers protection that is better or
comparable to many hardware based solutions, but costs tens of thousands less.

Double-Take replicates changes to files at the byte-level from any Windows Server to
any other Windows Server across any IP-based network. It installs on each server and
uses a file system filter driver to determine what changes are occurring to files and it
                                                                                                   Figure 2: How Double-Take Replicates
replicates those file operations to another server and applies them to a secondary
copy of the data. All changes are sent and applied in the exact order that they
occurred on the production system, guaranteeing a crash-consistent copy of data on
the secondary system.

One of the strengths of the replication technology from Double-Take is that it protects files at the byte level, regardless of the application. In
the case of email systems, when any of the email files and/or databases are changed (new mail, deleted mail, moves, etc.) only the actual
byte-level changes (not whole blocks or whole files) are copied to a target server. This greatly reduces the amount of traffic going over the
network to minimize any possible performance impact, while ensuring the lowest possible latency between the production data and the
remote replica. Once the data is protected on the target server, multiple solutions are available for achieving availability goals. And because
these solutions run on the host server, they are completely hardware and storage independent; capable of replicating data between any
storage device in any configuration, including Storage Area Networks (SAN), Direct Attached Storage (DAS), Network Attached Storage (NAS),
and iSCSI. With thousands of deployments, Double-Take has become the leader in protecting critical email environments, including Exchange,
Notes, BES, and others.

With asynchronous solutions such as Double-Take, there aren't inherent performance implications of other synchronous solutions, nor are
there any distance limitations which restrict the level of protection they can offer, allowing them to be deployed for complete disaster recovery
protection from local and regional outages. The host-based solutions from Double-Take can replicate email and BES data to any location
across the city or across the country. By taking advantage of its built-in bandwidth controls, compression and extended queuing features,
Double-Take uses current infrastructure to protect existing email environments while having minimal impact on production servers,
applications and networks.
                                                                                  Because there are no proprietary hardware requirements or the
                                                                                  need for particular types of storage at either end of the
                                                                                  replication stream, you are free to use any servers and storage
                                                                                  hardware whether it's components you already have or new
                                                                                  purchases you plan to make. If you already maintain multiple
                                                                                  data centers, you can simply replicate data between them, using
                                                                                  each as a DR site for the other, further reducing overall costs and
                                                                                  complexity and increasing the ROI on existing equipment. If you
                                                                                  have a relationship with a disaster recovery vendor or a storage
                                                                                  service provider, you can use Double-Take to replicate data
                                                                                  directly to your facility over a VPN or other secure connection.

                      Figure 3: Remote Replication


Keeping BlackBerry Users Connected
While it is crucial to ensure that the data is readily available, another factor that must be considered is the amount of time that it takes to
recover data after a failure. Downtime can quickly result in many lost dollars. The actual time to recover and rebuild from this replicated data
may be greater than a business can afford. So although email and BES data is being replicated to one or more remote locations, will users be
satisfied waiting until the data is restored and the application is brought back online? This leads to the next step to ensuring recoverability:
ensuring availability.

In the end, ensuring availability is what matters most - ensuring not only that the data is available, but that the application itself is available.
Both are needed to allow users to continue working in the event of an outage. However, the question remains - how can you ensure that in
all scenarios the email system and its wireless enhancements continue to be available to users, even during a failure?

Protecting BlackBerry Enterprise Server
Once a BlackBerry is on a carrier's network, it is linked to RIM's Network Operating Center (NOC), which has direct connections to all of
RIM's carrier partners and to BlackBerry Enterprise Servers (BES) all over the world. The BlackBerry Enterprise Server (BES) software is
middleware that links handheld devices to corporate email services such as Microsoft Exchange and Lotus Notes.3

                                                             Figure 4: BES Configuration

Typically, BES is deployed on a separate server from the actual mail server, although Lotus Notes does allow it to coexist on the same server
as users' mailboxes. When ensuring the availability of BES, typically there are the same challenges as with the email server itself. The BES
protection requirements are likely going to be the same as email requirements, so similar solutions can be deployed. BES uses Microsoft SQL
Server to store its configuration information. Without this data, the entire BES application is inoperative, resulting in BlackBerry users being
"down". While BES is designed to allow a simple manual failover process of its services to a backup server should the production server or
services fail, it does not provide data replication to protect against a failure or corruption of the SQL Server database. In order to have a fully
protected BES environment, you must ensure that the SQL Server data is readily available and that a redundant server with the BES
application installed is ready to go should it become necessary.

3 Mahmoud, Qusay H. "Programming the BlackBerry with J2ME." April 2005


High Availability with Double-Take
Whether BES is running on the mail server or on a separate server, Double-Take can ensure that all of the data is protected on a secondary
server and can facilitate the failover should a failure occur. First, a new server (either a physical machine or virtual machine) is provisioned at
the recovery site. BES is then installed on the new recovery server along with any requisite software such as Microsoft SQL Server. Then
Double-Take is installed on both the production and secondary servers. When not being used for failover purposes, the BES services are
stopped on the secondary server and are automatically started only when an outage occurs.

Double-Take is then configured to replicate the BES configuration database and other related data files from the production system to the
secondary system using its real-time, byte-level replication. Double-Take is also configured to continuously monitor the availability of the
production BES. If a failure is detected, it can automatically switch BES processing from the production server to the backup server, start all
BES services on that server, and run all necessary maintenance jobs required by BES. This provides a quick, efficient and automated method of
ensuring that the Blackberry system is back online and available to users in the fastest possible manner, often before users are even aware
there was a failure. Most importantly, the architecture does not require the reconfiguration of any BlackBerry handhelds or the RIM BlackBerry

More detailed configuration and setup information for protecting BlackBerry Enterprise Server is available in the Double-Take Software
Application Note entitled, "Guidelines for using BlackBerry® Enterprise Server with Double-Take®".

                                                Figure 5: Protecting BES with Double-Take


When considering the myriad of technologies and applications used in many corporate environments, it can be difficult to find vendors and
solutions that support a wide range of different needs. Because Double-Take replication technologies provide the flexibility of being
application independent, the same level of data protection used in tens of thousands of deployments to protect business-critical applications
such as Exchange, SQL Server and Lotus Domino can be used to provide the same level of protection and recoverability for BlackBerry
Enterprise Server. By replicating BES data continuously, in real-time and combining that up-to-date copy of the data with the ability to
monitor and failover the BES application, mobile users can remain connected to co-workers, partners and employees, even during any disaster
or outage.


   About Double-Take® Software
   Double-Take® Software provides the world's most relied upon solution for accessible and affordable data protection for Microsoft® Windows®
   applications. The Double-Take product is the standard in data replication, enabling customers to protect business-critical data that resides
   throughout their enterprise. With its partner programs and professional services, Double-Take delivers unparalleled data protection, centralized
   back-up, high availability, and recoverability. It's the solution of choice for thousands of customers, from SMEs to the Fortune 500 in the
   banking, finance, legal services, retail, manufacturing, government, education and healthcare markets. Double-Take is an integral part of their
   disaster recovery, business continuity and overall storage strategies. For more information, please visit www.doubletake.com.

   Double-Take Software Headquarters                                                                Double-Take Software Sales
   257 Turnpike Road                                                                                8470 Allison Pointe Blvd. Suite 300
   Southborough, MA 01772                                                                           Indianapolis, IN 46250
   Phone: +1-800-964-0185 or +1-508-229-8483                                                        Phone: +1-888-674-9495 or +1-317-598-0185
   Fax: +1-508-229-0866                                                                             Fax: +1-317-598-0187

   Or visit us on the web at www.doubletake.com

                                                                                               Get the standard today: www.doubletake.com or 888-674-9495

© 2007 Double-Take Software. All rights reserved.
Double-Take, GeoCluster, and NSI are registered trademarks of Double-Take Software, Inc. Balance, Double-Take for Virtual Systems, and Double-Take for Virtual Servers are trademarks of Double-Take Software,
Inc. Microsoft, Windows, and the Windows logo are trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries. All other trademarks are the property of their
respective companies.

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