The Zerto solution 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.

The following are described in this section:

Disaster recovery using the Zerto solution 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.

A recovery operation is one of the following:

 

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 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 34 for more details about the journal.

To recover files and folders, see “Recovering Files and Folders”, on page 178.