Continuing Data Protection in the Era of Virtualization

media_assets_server_replication_.pngWhen looking closely at data backup strategies, you will notice that there are several methods in the planning of data backups. Each data backup plan addresses a Service Level Agreement and employs a strategy that aligns with the criticality of the workload to be protected.

For the last ten years, the Veeam company has offered backup and replication products, covering backup, recovery, and near continuance data protection to meet the requirements of the backup strategies.

With the most recent announcement of the new Veeam CDP (Continuous Data Protection) feature, Veeam will continue its advance into the enterprise data protection market. With this new feature added, Veeam will now cover all aspects of SLA requirements in the Backup space.

To offer a CDP, a software vendor like Veeam must develop a filter driver to intercept the Input/Outputs, (IOs) and then replicate these IOs to a standby server to keep it as near as possible to identical as the production server, to be ready for instant recovery and failover in the event of a disaster. The CDP technology shortens the Recovery Point Objective (RPO) to seconds, the requirement for protection of a critical workload.

How does Veeam achieve CDP while offering an agentless data protection of the virtual environment; and this while not using their new agent for Windows and Linux?

In order to deliver a CDP product, Veeam R&D has taken the path of utilizing the new VMware vSphere API for I/O filtering (VAIO) technology, introduced with ESXi 6.0, Update 1.  The VAIO framework enabled Veeam to develop a filter driver that runs inside the ESXi host and to intercept IO requests directed from the guest VM to the VMDK file (i.e. virtual disk). After the Veeam filter driver has been deployed on the ESXi host, any IO request issued or committed to the disk must pass and be processed by the Veeam IO filters.

It is important to note that though the Veeam filter is deployed on the ESXi host, it runs as a VM-level component; it is not an ESXi Host component. The outcome of that approach means that if is any problem or issue occurs with the filter driver, it will not affect the ESXi host; it will be isolated to the specific VM protected by the Veeam filter.

How Veeam filter is Using the VSIO

The VSIO framework connects several layers of the virtual infrastructure to provide the overall framework. To understand how Veeam R&D utilized the API, we must define two terms:

The Initiator = guest VM and The Consumer = VMDK

IO requests moved between the initiator and the consumer will be filtered by the Veeam filter driver. The requests are then intercepted and replicated to the target machine through the CDP proxy.

The figure below illustrates the configuration panel to set up the CDP Filter.


 Installing the Veeam CDP filter driver

On installing the filter driver, the filter will automatically attach to each running VM process (VMX process). The filter directs all IO to a daemon, and all data streams will pass through the new Veeam CDP proxy via a VM bus if the CDP proxy is deployed as a VM. Alternatively, Enterprise customers can deploy the CDP proxy as a physical machine, and then use a dedicated Network Interface Card (NIC) to process backups to avoid the processing overhead of passing filter data through the VM Bus. The CDP proxy uses a caching mechanism to manage the volume of filter data to prevent a data bottleneck.



Veeam CDP Architecture

The Veeam CDP uses policies to manage processes, rather than using job settings; the CDP is always in the run mode. By default, the Veeam CDP offers a 15 second RPO; this parameter can be changed to align it with your particular SLA agreements, or your data processing bandwidth. For example, the lower the RPO, the faster the bandwidth requirements.

The figure below illustrates an early release screenshot showing the configuration of the Veeam CDP policy.


CDP Policy Configuration



It is an exciting time for Veeam; the new CDP feature will put Veeam in a dominant market position in the data protection and backup space. The new Veeam CDP technology is based on the VMware framework, supported by VMware. To take advantage of the new Veeam CDP capability, you will need a VMware Standard Edition, or above.

This is an early review of the Veeam CDP; we will revisit this feature when Veeam R&D releases CDP to Beta Testing. Our blog will be updated then, as Veeam R&D is sure to surprise us with more cool features.

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