// Module included in the following assemblies:
//
// * virt/backup_restore/virt-disaster-recovery.adoc

:_mod-docs-content-type: CONCEPT
[id="virt-vm-behavior-dr_{context}"]
= VM behavior during disaster recovery scenarios

[role="_abstract"]
VMs typically act similarly to pod-based workloads during both relocate and failover disaster recovery flows.

[id="dr-relocate_{context}"]
== Relocate

Use relocate to move an application from the primary environment to the secondary environment when the primary environment is still accessible. During relocate, the VM is gracefully terminated, any unreplicated data is synchronized to the secondary environment, and the VM starts in the secondary environment.

Because the VM terminates gracefully, there is no data loss. Therefore, the VM operating system will not perform crash recovery.

[id="dr-failover_{context}"]
== Failover

Use failover when there is a critical failure in the primary environment that makes it impractical or impossible to use relocation to move the workload to a secondary environment. When failover is executed, the storage is fenced from the primary environment, the I/O to the VM disks is abruptly halted, and the VM restarts in the secondary environment using the replicated data.

You should expect data loss due to failover. The extent of loss depends on whether you use Metro-DR, which uses synchronous replication, or Regional-DR, which uses asynchronous replication. Because Regional-DR uses snapshot-based replication intervals, the window of data loss is proportional to the replication interval length. When the VM restarts, the operating system might perform crash recovery.
