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Zerto 2020 Update

Most people know Zerto for disaster recovery services. In reality the market has changes since 2011, as has Zerto, now covering:

  • DR
  • Operational recovery
  • Long term retention
  • Hybrid, multi-cloud
  • Operational services

The Zerto solution is a single platform deployed irrespective of the services to be consumed. Everything is based upon continuous data protection.


2019 – So what did Zerto do last year?

Through feedback Zerto found that organisations were asking for the following additional requirements of their product.

  • Restore data from a recent copy from mins to days old
  • Recover from disaster events to a remote site and/or cloud
  • Retain data for years to keep my regulators happy
  • Move applications and data without disruption

A Zerto journal can store up to 30 days on premise but usually 8 days is configured, then 3 days on the DR infrastructure, you can now take that journal data and archive it for long term retention. Allows you to essentially deliver backup like solution for DR with no/minimal impact to production.

Long term is a repository of your choice to obtain the best cost efficiencies possible. You can store this for as long as you see fit.

Zerto want to break-up data protection providing an efficient, cost effective RPO & RTO offering that meets your demands.

Another area that Zerto have enhanced through 2019, was their ransomware protection.

With the growing demand of hybrid and multi-cloud architectures Zerto in 2019 enhanced their integration into the Microsoft Azure platform:

Specifically obtaining support for D series instances and VNET peering support.


Zerto found through the expansion within Azure that to meet their demanding RPO and RTO requirements from customers within Azure they needed to move their cloud based architecture to be more cloud-native. Utilising Azure Queue and VM scale sets to deliver faster recovery, reduced management overhead and further scalability than what was possible in the early release supporting Azure.

2020 – Zerto Version 8 Release!

On the 24th March Zerto released version 8 of their product. This was to expand data protection and recovery capabilities across on-premises and cloud platforms.

Specifically in this release Zerto have provided the following:

  • GCP support for VMware on Google CloudVMware
  • vVol support
  • Azure
    • Support for Gen2 VMs
    • Simplified VM failover to Azure
    • Failback functionality as part of the cost-effective incremental snapshots of Azure managed disks is now available across ALL regions
  • AWS storage gateway support for cloud archive and data protection
  • New single pane of glass
  • New impact analysis capability to mitigate risk of an organization’s protected and unprotected environment for on-premises or cloud.
  • New resource planning view of Unprotected VM’s for better insight into an organizations’ unprotected VMs.
  • Additional features to automate and streamline the processes for failover and configuration in the public cloud with automated OS configuration, automatic failback configuration and more.

Zerto and VMware on Google Cloud Platform

Akin to the VMware Cloud on AWS solution available, there is an expected GA of VMware on GCP circa June 2020. With this announcement, Zerto have looked to provide day zero integration and support for data protection.

The initial solution will support native VMware configurations, replication to GCP and GCP region to region replication.

An overview of the architecture can be seen below.

This additional functionality provides Zerto with the capability and future expansion of services across any cloud, which aligns with their corporate plan/approach.

AWS Enhancement

Within Zerto 8.0, they removed the manual requirements and inject drivers on failover. Within AWS you can now obtain the following:

With Zerto integrations with AWS, Zerto have decided to leverage a native platform within AWS to assist in providing long term retention of Zerto journals/metadata. This will utilise, AWS Storage Gateway.

This will provide a local cache for fast recovery, and a relatively low storage cost for long term retention.

Zerto found speed limitations with AWS APIs, so built their own import mechanism. When building their own mechanism they found that manual installation of drivers etc was needed.

Microsoft Azure Enhancement

Zerto 8 provided the following enhancements for Azure integration:

The most critical update here in my opinion is the streamline of the entire failover and failback cycle. This allows organisations to simplify their DR runbooks for failover scenarios.

VMware Enhancement

Zerto have now brought support for VMware vVols. This is to assist in providing continuos data protection rather than snapshots, enabling storage agnostic data protection and migration from/to/between vVols and non-vVol datastores.

Zerto 8 – Platform Updates

 The first update is a new recovery user interface. This was the first requirement in enabling the rapid reverse functionality.

The aim for rapid reverse for workload mobility is to allow migration, conduct of tests and perform failovers with more availability.

Reverse protection ensures a VPG migrated to a 2nd site can remain easily protected by replicating back to the same site that previously hosted it. In Zerto 8.0, the sync performed after a committed move operation has been changed from a delta sync to a much faster bitmap sync. This can improve the ability to meet or outperform protection SLAs.

Delta Sync vs Bitmap

A Delta Sync uses a checksum comparison to minimize the use of network resources. A Delta Sync is used when the protected virtual machine disks and the recovery disks should already be synchronized, except for a possible few changes to the protected disks, for example:

  • When a virtual machine was added to the VPG and the target recovery disk is defined as a pre-seeded disk
  • After a source VRA upgrade of a major release: Depending on the nature of the upgrade, a VRA upgrade on the protected side may trigger either a Delta Sync or a Bitmap Sync. See the version release notes to determine if a sync will be triggered with a source VRA upgrade
  • For reverse protection after a move or failover
  • A Force Sync operation was manually initiated on the VPG
  • A host protecting virtual machines was restarted and the protected virtual machines on the host had not been vMotioned to other hosts in the cluster or a protected virtual machine was vMotioned to another host without a VRA, and then vMotioned back to the original host

Whereas, Bitmap sync uses a change tracking mechanism of the protected machines during a disconnected state or when a VRA buffer is full. In these situations, Zerto Virtual Replication starts to maintain a smart bitmap in memory, in which it tracks and records the storage areas that changed. Since the bitmap is kept in memory, Zerto Virtual Replication does not require any LUN or volume per VPG at the protected side. The bitmap is small and scales dynamically, containing references to the areas of the protected disk that have changed but not the actual I/O. The bitmap is stored locally on the VRA within the available resources. For example, when a VRA goes down and is then rebooted.
When required, Zerto Virtual Replication starts to maintain a smart bitmap in memory, to track and record storage areas that change. When the issue that caused the bitmap sync is resolved, the bitmap is used to check updates to the protected disks and send any updates to the recovery site. A bitmap sync occurs when any of the following conditions occur:

  • Synchronization after WAN failure or when the load over the WAN is too great for the WAN to handle, in which case the VPGs with the lower priorities will be the first to enter a bitmap sync
  • When there is storage congestion at the recovery site, for example when the VRA at the recovery site cannot handle all the writes received from the protected site in a timely fashion
  • When the VRA at the recovery site goes down and is then rebooted, for example during a Zerto Virtual Replication upgrade

In Zerto 8.0, if you perform a move and then choose to reverse protect it will then do a bitmap sync automatically. This will keep in sync and make more efficient at reverse protect. Zerto are looking to remove delta sync on all failover mechanisms moving forward.

Extend VPG to LTR

Zerto have released application aware retention allowing you to consistently protect and recover based on your VPGs and push to LTR. This will provide protection from seconds to years.


Zerto Analytics is Saas delivered and optional for Zerto customers, but it is free for you to use!

The new capabilities are as follows:

  • Unified alert management
    • Configure alerts and notifications across Zerto platforms
  • Visualise unprotected VMs
    • Identify unprotected VMs at risk
    • Forecast resource requirements of protecting the VMs
  • Long-term retention reporting
    • Complete view of protected VMs, from short and long term
    • Status, capacity and troubleshooting capability
  • Efficient resource planning
    • Forecasting
      • Shows protected environments for forecasting of compute, network, storage, recovery disk size and journal size
    • Data driven decisions
    • Accurately cost your protection in the public of private cloud

I hope you found the overview of Zerto in 2019 and updates for Zerto 8 in 2020 useful. One final update is that ZertoCon 2020 is taking place as a digital conference on May 20th. Sign up at

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