VM Replication
VM Replication creates and maintains a copy of a VM on another host. After the initial full copy, later replication sessions copy only changed data blocks according to the configured schedule.
VM Replication is a disaster recovery capability intended to reduce downtime and data loss.
Definition
VM Replication keeps an up-to-date copy of a source VM in a target environment. The replica can be used when the source VM is unavailable.
Replication vs. Backup
| Capability | Description |
|---|---|
| Backup | Copies physical or virtual files and databases to a secondary location for recovery when needed. |
| Replication | Maintains up-to-date copies of entire VMs in a second location for failover if the primary source fails. |
Backup and replication are complementary recovery capabilities. Use backup for recovery points and replication for a VM copy that can be failed over when the source VM is unavailable.
Features
| Feature | Description |
|---|---|
| Continuous Data Protection (CDP) | Replicates changes from the source VM to the target environment. |
| Replication schedule | Supports schedules such as every 4 hours, every 8 hours, daily, weekly, or monthly. |
| Manual failover | Allows manual initiation of failover to the disaster recovery environment. |
| Operating-system independent replication | Runs independently of the VM operating system and applications. |
| Centralized management | Provides portal-based management for both source and replicated VMs. |
| Data deduplication | Filters unnecessary data blocks and performs deduplication. |
Use Cases
- Replicating VMs to a geographically distant site to protect against regional incidents.
- Preparing a disaster recovery environment with scheduled replications.
- Including VM replication in a business continuity plan.
Prerequisites
Before requesting replication, make sure these prerequisites are in place:
- Target environment is available.
- Private IP is available in the target environment.
- Network is available in the target environment.
Step-by-Step Guide
Request replication
- Open Compute.
- Select Virtual Machine.
- Choose the VM to replicate.
- Open the Replication tab on the source VM.
- Select Manage Replication.
- Choose a destination environment for the replica.
- Select a replication regime, such as every 4 hours, every 8 hours, daily, weekly, or monthly.
- Click Submit.
Private IP availability
The portal shows a green note if the private IP is available in the destination environment. If the private IP is not available, a red message prevents replication creation.
Manage replication
The replication table shows activities performed according to the configured replication regime, including date, time, status, and output.
To disable replication, enter the confirmation word and click Yes, Make Standalone. This disables replication and converts the destination VM into a standalone VM.
Source VM requirements while replication is enabled
While replication is enabled:
- Network interfaces cannot be added or removed.
- Each source VM is limited to one replica.
- The source VM cannot be deleted until replication is off.
Manage the replica
Firewall rules are not replicated from the source VM. They must be managed manually on the replica.
Allowed replica firewall rule actions:
- Add firewall rules.
- Delete firewall rules.
- Edit firewall rules.
Glossary
| Term | Meaning |
|---|---|
| VM | Virtual machine. |
| DR | Disaster recovery. |
| CDP | Continuous Data Protection. |
| Replica | The replicated VM copy in the target environment. |