Overview of Recovery Flows

Zerto Virtual Replication enables protecting virtual machines, for both disaster recovery or for extended, longer term recovery from a retention repository, by protecting the relevant virtual machines in virtual protection groups. A virtual protection group (VPG) is a group comprised of virtual machines that are grouped together for recovery purposes. For example, the virtual machines that comprise an application like Microsoft Exchange, where one virtual machine is used for the software, one for the database, and a third for the Web Server require that all three virtual machines be replicated to maintain data integrity.

Once a VPG has been created, each virtual machine in the VPG can be replicated on the recovery site under the VRA on the host specified in the VPG definition as the host for the recovery of the virtual machine.

In addition to disaster recovery and recovery from retention, Zerto Virtual Replication enables recovery of individual files or folders from a certain point of time.

The following are described in this section:

Disaster recovery using Zerto Virtual Replication enables recovering from a disaster to any point between the moment just before the disaster and a specified amount of time in the past up to 30 days. The recovery is done in real time at the recovery site with a minimal RTO.

Every write to the protected virtual machine in a VPG is copied by the VRA on the same host as the protected machine and passed to the VRA in AWS. The VRA writes these transactions to buckets in S3. This information is ready to be written to EBS disks in EC2 when recovering from a disaster or when recovering a retention set.

Virtual machines are protected in VPGs, which are defined in the protected site. Once a VPG is created, Zerto Virtual Replication creates a copy of the protected virtual machines under the management of a Virtual Replication Appliance, VRA, on the AWS recovery site. The data managed by the VRA is saved in an S3 bucket.

When a recovery operation is performed, the VRA creates the virtual machines defined in the VPG in EC2 and imports data from the S3 bucket as EBS disks in EC2.

After initializing the VPG, all writes to the protected virtual machines are sent by the VRA on the relevant host for each virtual machine on the protected site to the VRA on the AWS recovery site. The information is saved in the journal for the virtual machine with a timestamp, ensuring write-fidelity. Every few seconds the Zerto Virtual Manager causes a checkpoint to be written to every journal on the recovery site for every virtual machine in the VPG, ensuring crash-consistency.

The data remains in the journal until the time specified for the journal when it is moved to the relevant mirror disks in S3, also managed by the VRA for the virtual machine. In this way, you can recover the virtual machines using the mirror disks and the data from the journal to include the final few hours of data for each virtual machine. Refer to “The Role of the Journal During Protection”, on page 27 for more details about the journal.

When testing that the recovery works as planned, the Zerto Virtual Manager (ZVM) creates the virtual machines defined in the VPG in EC2. The following references the procedure to recover virtual machines:

You can recover specific files and folders from the recovery site for virtual machines that are being protected by Zerto Virtual Replication and running Windows operating systems. You can recover the files and folders from a specific point-in-time.

To recover files and folders, see “Recovering Files and Folders”, on page 169.

NOTE:

You cannot restore a retention set in Azure, or in AWS.

For Azure environments, use Windows Azure Backup to restore VPGs.

If you need to extend the recovery ability to more than the 30 days that are available with disaster recovery, Zerto Virtual Replication provides Long Term Retention that enables saving the protected VPGs for up to one year in a state where they can easily be deployed.

During the retention process, data from the recovery VPGs is saved in a repository as repository sets that can extend as far back as a year. These repository sets are fixed points saved either daily, weekly or monthly.

When a Retention process starts, the DSS communicates with the VRA on the recovery site to create the retention sets of the VPGs, and saves these sets in the repository.

To set up Long Term Retention to protect VPGs, see “Using Zerto’s Long Term Retention”, on page 183. Configuring Long Term Retention is part of defining a VPG.

After initializing the VPG, Zerto Virtual Replication periodically checks that the time to run a Retention process has not passed. At the scheduled Retention process time, the Retention Process is run and the retention set is stored in the specified repository.

Retention sets are kept for the retention period specified in the VPG’s Retention Policy. Over time the number of stored retention sets are reduced to save space.