There are multiple services designed to backup and replicate Virtual Machines in your private or public virtual environments. However, very few are able to replicate and protect a physical server. And yet, many companies need to protect both virtual machines and physical servers because of legacy applications running on legacy infrastructure. Double-Take is an agent based replication software that allows replication between similar Operating Systems. Because this replication takes place at the OS level, Double-Take is able to protect physical Linux and Windows server to a Virtual Machine in iland’s cloud environment.
The Double-Take Components
Double-Take uses agent based Operating System to Operating System replication. This means that all of the functionality and processing takes place in the Operating System. It is because of this that a Physical Server can replicate to a Virtual Server and vice versa. This also limits the amount of servers required for replication. At a minimum, Double-Take requires a Source Server (the server to be protected or migrated) and a Target Server (the server being replicated or migrated to). Unlike other products like Veeam and Zerto, you do not need to add Proxies, or Replication Appliances, VM Managers or Repositories. However, iland does recommend creating one server on the target side to be used to manage the environment. This server does not require a license, but allows you to monitor and manage all servers and jobs involved in your Double-Take Replication environment. It also helps you revert back from failover tests and push installations to new servers.
This management server does not require an active license to administer the Double-Take environment and can be provisioned with the help of iland’s Cloud Services team. Iland engineers will be available to help you install the Double-Take console on this server and connect to other servers your wish to replicate. Essentially, this Double-Take Management server will act as the brains of the replication or migration project. From here, the next step is installing Double-Take on the Source and Target servers. This can be done by manually installing the software on the servers or pushing the installation from the Double-Take Management Server. For instructions on installing Double-Take, please refer to this document: iland_Installing_Double-Take
The source server and target server should be similar in hardware specifications as well as Operating System. For instance, if you have a physical server with 2 CPU, 4GB RAM, a 100GB C: drive and a 200GB E: drive, you will want to build a Virtual Machine with the same hardware specs. You will also want to match the OS version, so if the physical server is running Windows Server 2008 R2 Datacenter, you should have the same OS version on the target server. With the source and target servers deployed and Double-Take installed, you are ready to create a Double-Take replica job.
Replication and Failover
Double-Take allows for multiple forms of replication. You have the ability to use Files and Folder replication, SQL and Exchange replication or Full Server replication. Files and Folder replication may be used if you would rather rebuild a legacy physical server as this type of replication does not require the same OS version. You could build a Windows 2012 R2 VM to replace an old physical file server and replicate just the user or shared folders.
SQL or Exchange replication allows for you to create redundancy between SQL/Exchange physical servers as well as clustered environments. Instead of protecting the raw Files and Folder data, this replication actually protects and copies the SQL or Exchange database. This, could also be used when converting an existing physical Exchange or SQL server to your virtual environment. Full Server replication replicates the entire source server including all files, folders and applications. This replication allows you to fully convert a physical server to a virtual server or failover a physical server in a virtual environment.
A Full Server failover will reboot the target server. When the server powers back on, it will have received and reimaged itself to completely mirror the source server. This means that the target server will have the exact same hostname, IP, registry, user login information as the source server. Effectively, when the failover completes, the target server “becomes” the source server. This is the recommended method when protecting or migrating an entire physical server as it easily and quickly converts the box into a virtual machine. Since the target will be a virtual machine in the iland cloud, there is always a revert or failback option by taking a snapshot of the target server. Again, iland engineers are always available to not only assist in setting up replication but also testing and performing a failover. Here’s a useful reference document on creating replica jobs in Double-Take: iland_Creating_Replica_Jobs_in_Double-Take
There are many advantages to having one DR solution and cloud provider for your entire IT footprint – both virtual and physical – and the iland solution with both Zerto and Double-Take enables that. Here’s an example
of one of our customers – a law firm in New York City – that has had success with protecting both their physical and virtual machines.