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December 10, 2021

VMware vSphere Replication

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VSphere replication is essential for business continuity and disaster recovery, enabling organizations to protect their virtual workloads off-site.

With VMware vSphere Replication, you can quickly and easily protect virtual machines regardless of essential storage technologies, freeing organizations from lockout storage and simplifying management.

vSphere Replication grants an efficient hypervisor-based replication process for virtual machines running in the VMware vSphere environment.

With advanced delta mechanisms, strategies, and integrated compression capabilities, vSphere replication server can efficiently transmit data over long distances. However, a vast area network (WAN) can introduce additional complications that limit replication bandwidth.

When the WAN establishes a connection between the two data centers, it has latency, limited bandwidth, or packet loss; replication bandwidth may be adversely affected, resulting in missed RPO targets or unsuccessful replication attempts. It puts your business at an additional risk of losing data in the event of a disaster.

How To Protect Your VMs with vSphere Replication

An essential part of IT protection is to ensure that the services provided by virtual machines are flexible and robust at all levels of the computing chimney, from hardware to application. vSphere Replication management server enhances the recovery capabilities of the vSphere platform by providing a built-in ability to replicate a running VM to another location continuously.

VSphere Replication environment increases the offers in the vSphere access protection matrix. The replication creates a copy of the VM that can be stored locally in a cluster or other location, providing a data source for a quick VM recovery point objective RPO within minutes. Provides a solution that offers better recovery time than backup without the complexity of a complete replication configuration based on a storage array.

vSphere Replication lets you configure VM-based replication and significantly enhances the protection features offered by vSphere. vSphere Replication copies the VM to another location, in or between clusters, and makes that copy available for recovery through the vCenter Server-based web interface.

Continues to protect the VM on an ongoing basis and repeats the changes made to the VM over the copy. This ensures that the VM is protected and accessible for recovery without backup. vSphere Replication is provided as a free component of all eligible vSphere licenses ranging from vSphere Essentials Plus to Enterprise Plus Edition.

Virtual machine protection is a critical data center oversight platform with VMware Data Protection backups. Unified vSphere Replication management is provided through the web client on the vCenter server. That being said, VMware vCenter server instances provide a familiar and agreeable screen for all aspects of virtual data center management, including many parts of protection such as replication, backup, and recovery.

Deploying vSphere replication virtual appliance

The VR device is a dual-core 64-bit SUSE Linux VM that comes pre-configured with 4 GB of RAM and two virtual disks of 10 GB and 2 GB. The VR device is deployed like any other OVA file using the Deploy OVF Template wizard. It is worth transcribing that the VR device is not DNS sensitive, unlike the previous version or the VDP device (discussed earlier).

You need to deploy the device on the ESXi 4.x host, but keep in mind that the device itself only configures and manages replication.

What follows the VMDK source changes is the ESXi 5.x VR agent, which sends the data (via the VR device) to the network file copy (NFC) component of the receiving host, which means that the VR device needs to communicate with management with the host network for replication to succeed.

Tips to protect virtual machines

You can protect virtual machines from partial or complete site failures by replicating virtual machines between the following locations:

  • From source location to destination location
  • Within one location from one cluster to another
  • From multiple source locations to a standard remote target location
  • It can be used as a “replication engine for VMware vCenter Site Recovery Manager”. (Will I talk about this in detail in my next post, a step-by-step procedure for integrating SRM with vSphere Replication and how it is used to protect VMs?)
  • It can also be used as a “replication engine for VMware vCloud Air Disaster Recovery”

Seeding virtual machines at the destination

We chose to sow the replications for the smaller sizes by restoring the backup to the image level of the cluster destination and then using these .vmdk files as the replication targets. Much better than storing 100 GB via WAN! vSphere Replication will check the files and transfer only the changed data; The specific numbers I saw are that for a recent (2-3 day old backup) on a 100 GB replicated virtual machine, this will switch to 2-4 GB changed blocks.

vSphere Replication with an initial full synchronization

vSphere Replication will make initial full synchronization of the source VM and its replica; if desired, a copy of the destination data can be set up to reduce the time and bandwidth required for the initial replication.

Once the baseline synchronization is complete, vSphere Replication switches to transferring only data blocks that have been changed. The vSphere kernel itself tracks unique entries in the disk files of protected virtual machines.

Identifies and replicates only those blocks that experienced outstanding records during the configured point of return point.

This ensures that a minimized amount of data is sent over the network to the target and allows aggressive target points to be recovered. Once unique information has been shipped, it should not be resent.

Only changes will be replicated, and blocks will be sent to the vSphere Replication Appliance at the target location. The data is received and checked at the target location in the vSphere replicator: only entirely consistent information is then stored on the vSphere hosts on the target cluster and thus on the disk.

This way of waiting for an entirely consistent block group ensures that the virtual machine replicates recovery at any time, even if data is lost during transit or crashes at any point in the transmission.

Conclusion

vSphere Replication is an exclusive feature of the VMware vSphere platform. vSphere Replication features are numerous.

vSphere Replication removes the requirement for replication to require identical storage hardware. Also, since the virtual machine replication will be “cold booted” when the upgrade is performed, the server hardware does not have to be identical if it is replicated between clusters.

Copy a virtual machine to another location, in or between clusters, and make that copy available to recovery via VMware vSphere Web Client or orchestrate a product for complete disaster recovery such as a VMware vCenter Site Recovery Manager.