Asynchronous or NearSync replication through Prism Element

How to set up asynchronous or NearSync replication through Prism Element

Last updated 29th June 2022

Objective

This guide details how to set up cluster replication via Prism Element.

OVHcloud provides services for which you are responsible, with regard to their configuration and management. It is therefore your responsibility to ensure that they they function correctly.

This guide is designed to assist you in common tasks as much as possible. Nevertheless, we recommend contacting a specialist service provider or reaching out to our community if you experience any issues.

Introduction

Via Prism Element, you can:

  • Add links to remote clusters.
  • Create protection domains to add replications to remote sites.

The Nutanix Standard OVHcloud pack allows you to use asynchronous replicas every hour.

For a shorter replication time between 1 and 15 minutes, you must configure NearSync replicas. This option is only available with the Nutanix Advanced OVHcloud pack.

Requirements

  • Two Nutanix clusters in your OVHcloud account
  • Access to the OVHcloud Control Panel
  • Access to your clusters via Prism Central
  • An interconnection between two clusters, e.g. via an IPsec VPN

Instructions

We will use two Nutanix clusters in OVHcloud data centres, one in Canada and the other in France, connected via an IPsec VPN, on two different IP addressing schemes which are:

  • 192.168.0.0/24 for the cluster in a data centre in France.
  • 192.168.10.0/24 for the cluster in a Canadian data centre.

If you need help setting up an IPsec VPN, please refer to our guide on interconnecting two Nutanix clusters through an IPsec VPN.

Connect via Prism Element to the cluster in France from Prism Central, as shown in this documentation: Nutanix Hyperconvergence.

Click Data Protection from the Home menu.

01 Create Remote Site From France01

Click Remote Site on the left side of the screen.

01 Create Remote Site From France02

Click + Remote Site to the right of the screen and choose Physical Cluster to add a remote site.

01 Create Remote Site From France04

Name the remote site in the REMOTE SITE NAME field, enter the IP address of the Prism Element of the remote site in France in the CLUSTER VIRTUAL IP field, and click Add Site.

01 Create Remote Site From France05

Scroll through the window using the scroll bar.

01 Create Remote Site From France06

In the Network Mapping section, select AHV:base in the Source Cluster and Destination Cluster drop-down menus. Then click the + button.

01 Create Remote Site From France07

If you have another VLAN, repeat the same operation with AHV VLAN: VLAN50. Click the + button to validate the association of source and destination networks.

01 Create Remote Site From France08

Choose default-container... from the Source VStore and Destination VStore drop-down menus. Then click the + button to connect the source and destination storage.

01 Create Remote Site From France09

Click Save.

01 Create Remote Site From France10

The remote site will then appear in the list.

01 Create Remote Site From France11

We will now connect to the Prism Element interface of the remote site in Canada and perform the same operation.

From the Home menu, click Data Protection.

02 Create Remote Site From Canada01

Click Remote Site on the left side of the screen.

02 Create Remote Site From Canada02

Click + Remote Site to the right of the screen and choose Physical Cluster to add a remote site.

02 Create Remote Site From Canada04

Name the remote site in the REMOTE SITE NAME field, enter the IP address of the Prism Element of the remote site in Canada in the CLUSTER VIRTUAL IP field, and click Add Site.

02 Create Remote Site From Canada05

Scroll through the window using the scroll bar.

02 Create Remote Site From Canada06

In the Network Mapping section, select AHV:base in the Source Cluster and Destination Cluster drop-down menus. Then click the + button.

02 Create Remote Site From Canada07

If you have another VLAN, repeat the same operation with AHV VLAN: VLAN50. Click the + button to validate the association of source and destination networks.

02 Create Remote Site From Canada08

Choose default-container... from the Source VStore and Destination VStore drop-down menus. Then click the + button to connect the source and destination storage.

02 Create Remote Site From Canada09

Click Save.

02 Create Remote Site From Canada10

The remote site will then appear in the list.

02 Create Remote Site From Canada11

Setting up inter-site replication

Now that the two sites are connected, we will create a protection domain with asynchronous replication containing three virtual machines located on the cluster in France to the remote site in Canada.

Return to the cluster’s Prism Element interface, located in France.

Choose Data Protection from the main Home menu.

03 Create dataprotection 01

In the Data Protection dashboard, click + Protection Domain in the top right-hand corner, then Async DR.

03 Create data protection 03

Name the protection domain and click Create.

03 Create dataprotection 04

Select three virtual machines and click Protect Selected Entities.

03 Create dataprotection 05

Click Next.

03 Create dataprotection 06

Click New Schedule to configure the schedule.

03 Create dataprotection 07

Modify this option to Configure your local schedule:

  • Enter Repeat every 1 hour.

Then enter the retention policies in Retention policy:

  • Choose locally and remotely keep the last 2 snapshots to keep two snapshots locally and remotely.

Click Create Schedule to commit the schedule.

03 Create dataprotection 08

The replication task is created to run hourly. This will be asynchronous replication, which can be used with the OVHcloud Nutanix Standard pack.

Click Close to close the window.

You can change the schedule to reduce the risk of data loss in the event of a disaster, but replication will switch from asynchronous to NearSync mode, and you will then need to upgrade your licence to the OVHcloud Nutanix Advanced pack.

03 Create dataprotection 09

The protection domain is created and appears in the list.

03 Create data protection 10

Virtual machine migration

Migrating VMs is an operation to move VMs that are members of a protection domain to the remote site without losing data. Both clusters must be online and communicate correctly with each other.

The migration steps are as follows:

  1. Stopping virtual machines on the source cluster (if they are turned on).
  2. Replication of missing data to destination cluster.
  3. Deleting virtual machines on the source cluster.
  4. Disable scheduling.
  5. Enabling virtual machines on the destination cluster.
  6. Replication is reversed, the destination becomes the source.

Go to the Prism Element interface where the replicated virtual machines are located.

In the Data Protection dashboard, click Migrate.

04 Migrate VM to Canada 01

Select the remote site, type MIGRATE, and click Migrate.

04 Migrate VM to Canada 02

The migration is then launched. It will be completed when the VMs appear at the remote site and are no longer visible at the original site.

Since the migrated virtual machines are turned off, you must start them manually.

04 Migrate VM to Canada 03

Virtual machine failover in case of disaster

If the original site is down, you can enable virtual machines that are members of a protection domain at the destination site.

Activation of virtual machines at the remote site will be done with the latest replicated data. For asynchronous replication, the maximum data loss risk is one hour.

Connect to the functional site with Prism Element.

Go to the Data Protection dashboard.

Select the site to activate and click Activate.

05 Active VM on remote site 01

Click Yes.

05 Active VM on remote site 02

The virtual machines will appear in the Prism Element console in the state of last replication. Data modified after the last valid replication will be lost.

Go further

Disaster Recovery Plan in Nutanix

IPsec interconnection between two sites

Nutanix Documentation on Data Protection and Disaster Recovery

Join our community of users on https://community.ovh.com/en/.


Did you find this guide useful?

Please feel free to give any suggestions in order to improve this documentation.

Whether your feedback is about images, content, or structure, please share it, so that we can improve it together.

Your support requests will not be processed via this form. To do this, please use the "Create a ticket" form.

Thank you. Your feedback has been received.


These guides might also interest you...

OVHcloud Community

Access your community space. Ask questions, search for information, post content, and interact with other OVHcloud Community members.

Discuss with the OVHcloud community