Business Continuity

Staying up while you recover: Double-Take Cloud provides easy server protection

Building a backup and disaster recovery service can be time consuming and costly. You need access to a data centre where you can site racks, servers, storage and have sufficient bandwidth to support the service. Alternatively, you could just take advantage of the cloud and leave your cloud supplier to take care of all that.

An increasing number of backup vendors are now releasing cloud-based versions of their products. Double-Take is about to release the new version of its cloud-based service, Double-Take Cloud 2.2. Here’s how you can use it to protect customers systems.

Backup and disaster recovery; phrases that are guaranteed to cause most people to adopt the thousand yard stare. They know they should be doing both yet often they have little idea of what if anything is actually taking place and while the basics are simple putting them into practice can be complex, especially when it comes to the crucial off-site component. As a result, this is one area where companies of all sizes are looking for outside assistance to help them solve the problem.

There are numerous solutions you can buy and install either at your own site or in a data centre to provide backup and disaster recovery to customers. But as the market for cloud-based services continues to mature, why go through the pain of building your own infrastructure when there are other solutions available to you that you can resell to your customers?

Ready-made Cloud

Software vendor Double-Take has a comprehensive portfolio of backup, disaster recovery, management, server and client provisioning software. Over the last two years it has been moving those products into the cloud to create a solution it calls Double-Take Cloud, to offer a server backup and disaster recovery solution.

Double-Take Cloud is currently based on Amazon’s EC2 platform (Vision Solutions, who has just purchased Double-Take, is considering alternative cloud providers although there are no announcements yet). That means that as well as getting a backup of the data on the servers you protect with this service, you can run the servers in the cloud while you repair or replace failed servers on site; recover an Exchange server to EC2 and it can receive SMTP email and let users read and send email using Outlook Anywhere or Outlook Web Access. The big changes in Double-Take Cloud 2.2 are around billing and a simpler user interface.

Before, you had two bills to deal with, from Double-Take and Amazon EC2. Customers will now get a single bill from Double-Take to make it easier to control costs and evaluate savings. Installation and setup is straightforward. Double-Take offers a free 30-day trial, although this is more of a ‘first month free’ offer than just a trial; you need to enter credit card details in order to sign up and remember to cancel before the end of the month to avoid being charged.

When signing up for the Double-Take Cloud, you also need to be careful with the Account Login Information. The email address and password you enter here will be your credentials for accessing the Double-Take Cloud and the Double-Take support site. Sadly, there is no ability to set a password or credential recovery point at this stage (something we feel Double-Take needs to address). Nor are these credentials part of your Active Directory or Domain Services.

Log in and you see your Repository Server, the names of any other servers you may have and your position in the workflow. The items in blue on the workflow are actions you need to take while the grey items are for information and link to the online help file. At the moment, there is no link between the Double-Take Cloud help files and the Double-Take Backup help files; for this to be a smooth solution, it needs a single help system across all the products.

The first step is to create a Repository Server. Amazon operates four regions where you can locate your servers; US-East, US-West, EU-West and Asia-Pacific. All backups taken by Amazon are kept in-region, according to their terms and conditions, which is essential for any company where data protection and compliance legislation is an issue. By default you get a 30GB hard disk for the operating system but you then need to add another disk for data storage. The default size for that drive is 50GB and if you need more you simply create a third drive which can be of any size, then delete the 50GB drive.

The next stage is to configure the firewall rules that control access. By default, access is from anywhere but you can limit the address range of the machines that can access your Double-Take Cloud instance. The system carries out the provisioning of all of the Amazon and Double-Take components in the background; this is dependent upon the state of the Amazon EC2 environment and it’s worth knowing that there could be a delay of several minutes (during this time, the screen is greyed out).

Once the backup repository server has been configured, the screen changes to show you the status of the server and two IP addresses ; the public IP address that has to be accessible through your firewall and the Private IP address that you will use to access the system. You can also see the Instance ID (an internal Amazon reference number) and the autogenerated password provisioned by Amazon which acts as the Administrator Password for the Repository Server. You’ll need this to connect to it using Microsoft Remote Desktop. Double-Take has provided a completed Remote Desktop instance to make life simpler during setup; save this to your local desktop to make it easier to launch each time you need it.

Once connected to the Repository Server, you need to download the application files. (In future you may be able to download these from the Double-Take site to reduce the amount of bandwidth you’ll be charged for by Amazon.)

Configuring the OpenVPN keys on the server can take up to ten minutes during which a Command box stays open on the desktop. (You don’t have to use OpenVPN but it is supplied and thus simpler than configuring another VPN solution.)

Once the master VPN key has been generated, you need to generate VPN keys for every server that you will be protecting; this is relatively quick. The keys are saved into a ZIP file that you download to C:\Program Files\OpenVPN\config on each server. OpenVPN runs as a service on each server and should be set to automatic. Check also that RDP is enabled on the server to be protected. This is done under System Properties > Remote.

One issue we found is that Amazon sometimes fails to properly allocate the second drive in the Repository Server; if this happens, go to Control Panel> Administrative Tools> Computer Management> Storage> Disk Management and make sure that you initialise and format the drive.

Now run Double-Take Backup to create the backup job. This is very simple. Select the Source and Repository Servers, what you want to protect (System State or Selected Data) and when you want snapshots to be taken. Although the Double-Take backup product supports Continuous Data Protection, Double-Take Cloud does not.

Now select where the snapshot image will be installed, the level of compression that you want to use (medium is the recommended setting) and whether you want to do bandwidth limiting. Finally select the route (which is the same IP address as the VPN server) and check the settings on the Protection Summary Screen. The first time you create the snapshot it will take a long time it and use a considerable amount of bandwidth. Double-Take is working on an option allowing you to take the first snapshot to disk locally and then transferring that out of band to the Repository Server. You would then establish a link and allow the delta files to take over the process from there.

Store and Recover

For disaster recovery, you need to configure a Recovery Server. By default, this will be in the same Amazon region as the Repository Server. You start by defining the IP address and then provision a server using the Amazon EC2 provisioning interface. There is a limit of 150GB for the boot drive but no limit for the user-defined disk which would normally be your data drives. As with the Provisioning Server, expect a delay while Amazon processes the server allocation.

Finally you run the Prepare Recovery Server option from the Double-Take Backup menu. This will push the Double-Take software to the Recovery Server, install .NET 3.5 onto your server and ensure that all the components can talk to each other.

Firm benefits in cloud

There are a lot of options for protecting data but few are as complete as the Double-Take Cloud solution. It has some shortcomings, but Double-Take is addressing many of them with plans to integrate help, provide an alternative download point for application files and offer methods for integrating security and logons into your AD or Directory Services. It has many benefits, from the simplicity of deployment to the ease and speed with which it can be provisioned (any delays are down to Amazon EC2 and its provisioning engine, or the creation and upload of the initial snapshot and here again, Double-Take is working on improving this).

Offline storage and recovery is a key part of any disaster recovery solution. By using the cloud, Double-Take offers you a readymade solution that you can deploy for customers to protect key data.


Sample Double-Take Cloud implementation
Replicate a Windows domain controller and Ex-change Server independently to the same repository server:

Using Amazon EC2
Tips on how to work with the EC2 service when using Double-Take:

Amazon Web Services Developer Forum
Announcements, discussions and tips on getting the most from EC2:

See Also

Volume1, Edition 1
Fail over not fall over
feature finder code 1132a


Double-Take Cloud 2.2
Price TBA

Setting Up Double-Take Cloud

  1. Setting up Double-Take Cloud requires provisioning servers in the right order.

  2. Pick the geographical region where you want to provision a Backup Repository Server.

  3. For security, you can limit the IP address range of machines that can access the cloud service.

  4. Once provisioned you need to record the two IP addresses, the Administrators password and use the Remote Desktop button to access the Repository Server.

  5. You can configure the Remote Desktop Connection to change the screen resolution, allocate local resources and set the performance.

  6. Once connected to the Repository Server you can download the Double-Take files and generate the VPN keys.

  7. Make sure that the source server has Remote Desktop turned on.

  8. Remember to initialise and format the second drive on the Repository Server.

  9. Run the Double-Take backup program and configure the source and Repository servers, the data to be protected and the transmission options.

  10. Provision the recovery server from Amazon EC2 making sure that the server type (x86/x64) and operating system match.

  11. Run the ‘Prepare a Recovery Server’ wizard from inside Double-Take backup.

  12. The ‘Prepare a Recovery Server’ wizard will copy the Double-Take software, install .NET 3.5 and check the communications between the Recovery Server and the Source Server.


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