Windows Server 2019 Module 7 section 1 Hyper-V Replica

Hyper-V failover clusters are used to make virtual machines (VMs)

highly available

Hyper-V Replica can protect against

data loss from natural disasters, and it can be used to implement an affordable business continuity and disaster recovery (BCDR) solution for a virtual environment

Hyper-V Replica can have two instances of a single VM residing on different Hyper-V hosts. How do these run

one is the primary and the other is the replica.

Replication engine

This component manages the initial replication, replication configuration details, replication of delta changes, and failover and test failover operations. It also tracks VM and storage mobility events and takes appropriate actions when necessary. For example, it pauses replication and Hyper-V Replica configurations when the source or the replica Hyper-V hosts are part of a Hyper-V failover cluster.

Change tracking chapter

This component tracks changes that occur to the VM on a source Hyper-V host. The change tracking chapter tracks write operations to the virtual hard disks (VHDs) regardless of where the VHDs are stored locally—on a storage area network, on a Server Message Block version 3 or newer share, or on a Cluster Shared Volume.

Network chapter

This component provides a secure and efficient way to transfer VM data between Hyper-V hosts. By default, the network chapter minimizes traffic by compressing data. It can also encrypt data when HTTPS and certification-based authentication are used.

Hyper-V Replica Broker

This component is used only when a Hyper-V host is a node in a failover cluster. This enables the use of Hyper-V Replica with highly available VMs that can move between cluster nodes. This role queries the cluster database. It then redirects all requests to the cluster node where the VM is currently running.

Management tools

With tools such as Hyper-V Manager and Windows PowerShell, Hyper-V Replica can be configured and managed. Use Failover Cluster Manager for all VM management and Hyper-V Replica configurations when the source or the replica Hyper-V hosts are part of a Hyper-V failover cluster.

Hyper-V replica can be set up

no matter the domain membership(doesn’t have to be part of the same domain)

The types of Hyper-V configurations

Both Hyper-V hosts are standalone servers. This configuration isn't recommended, because it includes only disaster recovery and not high availability.

The Hyper-V host at the primary location is a node in a failover cluster, and the Hyper-V host at the secondary location is on a standalone server. Many environments use this type of implementation. A failover cluster provides high availability for running virtual machines (VMs) at the primary location. If a disaster occurs at the primary location, a replica of the VMs is still available at the secondary location.

Each Hyper-V host is a node in a different failover cluster. This enables you to perform a manual failover and continue operations from a secondary location if a disaster occurs at the primary location.

The Hyper-V host at the primary location is a standalone server, and the Hyper-V host at the secondary location is a node in a failover cluster. Although technically possible, this configuration is rare. You typically want VMs at the primary location to be highly available, while their replicas at the secondary location are turned off and aren't used until a disaster occurs at the primary location.

Because each VM is configured for individual replication you must

plan resorces for each VM and how to configure their settings

Replica Server setting

Specifies the Computer name for fully qualified domain name (FQDN) of the replica server. If the replica server is a node in a failover cluster you should enter the name or FQDN of the connection point for the Hyper-V Replica Broker

Connection Parameters setting

If the Replica server is accessible, the Enable Replication Wizard populates the authentication type and replication port fields automatically with appropriate values. If the Replica server is inaccessible, these fields can be configured manually. However, you should be aware that you won't be able to enable replication if you can't create a connection to the Replica server. On the Connection Parameters page, Hyper-V can also be configured to compress replication data before transmitting it over a network.

Replication of VHDs setting

Replication Frequency

You can set replication frequency to 30 seconds, 5 minutes, or 15 minutes based on the network link to the Replica server and the acceptable state delay between primary and replica VMs. Replication frequency controls how often data replicates to the Hyper-V host at the recovery site. If a disaster occurs at the primary site, a shorter replication frequency means less loss as fewer changes aren't replicated to the recovery site.

Additional recovery points settings

You can configure the number and types of recovery points to send to a Replica server. By default, the option to maintain only the latest point for recovery is selected, which means that only the parent VHD replicates. All changes merge into that VHD. However, you can choose to create more hourly recovery points and then set the number of additional recovery points (up to 24). The Volume Shadow Copy Service snapshot frequency can be configured to save application-consistent replicas for the VM and not just the changes in the primary VM.

Initial replication method and schedule

Ms have large virtual disks, and initial replication can take a long time and cause a lot of network traffic. While the default option is to immediately send the initial copy over the network, if you don't want immediate replication, you can schedule it to start at a specific time. If you want an initial replication but want to avoid network traffic, you can opt to send the initial copy to external media or use an existing VM on the Replica server. Use the last option if a copy of the VM is restored at the Replica server and you want to use it as the initial copy.

Extended replication setting

you can replicate a single VM to a third server. Thus, a running VM can be replicated to two independent servers. However, the replication doesn't happen from one server to the two other servers. The server that's running an active copy of the VM replicates to the Replica server, and the Replica server then replicates to the extended Replica server.

Hyper-V Replica comes implemented when you install

Hyper-V

To enable Hyper-V replica do the following steps

Replication Configuration

Configure Hyper-V server settings

Specify Replica Server name and the connection options

Select the VHDs to replicate

Replication Health Data contains the following info

Replication State. This indicates whether replication is enabled for a VM.

Replication Type. This indicates whether you're monitoring replication health on a primary VM or replica VM.

Primary and Replica server names. This indicates which Hyper-V host the primary VM is running on and which Hyper-V host is the replica.

Replication Health. This indicates replication status. Replication health can have one of three values: Normal, Warning, or Critical.

Replication statistics. This displays replication statistics since the time that the VM replication started or since resetting the statistics. Statistics include data such as maximum and average sizes of a replication, average replication latency, number of errors encountered, and the number of successful replication cycles.

Pending replication. This displays information about the size of data that still needs to replicate and when the replica was last synced with the primary VM.

Test Failover

a nondestructive tasl the enables you to test a VM on a Replica Server while the primary VM stays online. The file with be appended with TEST to the end but will be offline.

Planned failover

used to move the primary to the replica secondary. Can be used for maintenance or if a disaster is expected to happen.

Failover

an unexpected failure of the primary VM, data and processes will move over to the replica

Other replication settings

Pause Replication. This action pauses replication for the selected VM.

Resume Replication. This action resumes replication for the selected VM. It's available only if replication for the VM is paused.

View Replication Health. This action provides data about the replication events for a VM.

Extend Replication. This action is available on the replica VMs, and it extends VM replication from a Replica server to a third server (the extended Replica server).

Remove Recovery Points. This action is available only during a failover. If you select it, all recovery points (checkpoints) for a replica VM are deleted, and their differing VHDs are merged.

Remove Replication. This action stops replication for the VM.

Site Recovery is a business contingency and disaster recovery (BCDR) solution to

replicates VMs to the cloud or a 2nd site