Veeam backup and replication for Disaster Recovery

General notes

Veeam backup and replication can be used for Hyper-V and VMware
Veeam replication comes with the license of Veeam backup. 
Veeam backup and replication Community Edition is free and can support up to 10 VM

Veeam backup and replication

You can create VM replicas with Veeam Backup & Replication. When you replicate a VM, Veeam Backup & Replication creates an exact copy of the VM in the native VMware vSphere format on a spare host and maintains this copy in sync with the original VM.

Veeam Backup & Replication lets you perform onsite and remote (offsite) replication for disaster recovery (DR) scenarios. To facilitate replication over the WAN or slow connections, Veeam Backup & Replication optimizes traffic transmission. It filters out unnecessary data blocks such as duplicate data blocks, zero data blocks, blocks of swap files and blocks of excluded VM guest OS files, and compresses replica traffic. Veeam Backup & Replication also allows you to use WAN accelerators and apply network throttling rules to prevent replication jobs from consuming the entire network bandwidth.

In Veeam Backup & Replication, replication is a job-driven process. To perform replication, you need to configure replication jobs. A replication job is a configuration unit of the replication activity. The replication job defines when, what, how and where to replicate. One replication job can be used to process one or several VMs. You can instruct Veeam Backup & Replication to run jobs automatically by schedule or start them manually.

Replication - User Guide for VMware vSphere

IP address assignment 

If you use different network and IP schemes in production and DR sites, in the common case you would need to change the network configuration of a VM replica before you fail over to it. To eliminate the need for manual replica reconfiguration and ensure minimum failover downtime, Veeam Backup & Replication offers possibilities of network mapping and automatic IP address transformation.

Network Mapping and Re-IP - User Guide for VMware vSphere

Replica Failover and Failback

In case of software or hardware malfunction, you can quickly recover a corrupted VM by failing over to its replica. When you perform failover, a replicated VM takes over the role of the original VM. You can fail over to the latest state of a replica or to any of its good known restore points.

In Veeam Backup & Replication, failover is a temporary intermediate step that should be further finalized. Veeam Backup & Replication offers the following options for different disaster recovery scenarios:

• You can perform permanent failover to leave the workload on the target host and let the replica VM act as the original VM. Permanent failover is suitable if the source and target hosts are nearly equal in terms of resources and are located on the same HA site.

• You can perform failback to recover the original VM on the source host or in a new location. Failback is used in case you fail over to a DR site that is not intended for continuous operations and would like to move the operations back to the production site when the consequences of a disaster are eliminated.

 Replica Failover and Failback - User Guide for VMware vSphere

Failover can be done as planned failover or failover by a click, like when you realize your primary server is down and you do failover by yourself. 

Using Veeam ONE, a monitoring tool, you can get notification to know the primary server is down and a failover needs to be done.