System Requirements for Continuous Replication

This topic summarizes requirements for continuous replication.

To avoid delays in replication, implement the following best practices:

  • Use a low latency network.
  • Provide enough cache space and a fast storage connection to the cache on the access node (VSA proxy) at the source site.
  • Provide a fast storage connection to the RP Store.
  • Provide enough storage for the RP Store.
  • Timestamps must be synchronized between access nodes and ESXi hosts.

Hypervisor Support

  • VMware

For detailed requirements, see System Requirements for Virtual Server Agent with VMware.


  • A disaster recovery VM license is required for continuous replication using VAIO.

vCenter and ESXi Requirements

  • vCenter Server version: 7.0, 8.0
  • ESXi version: 7.0, 8.0
  • ESXi memory requirement for each VM: 100 MB
  • Either a Standard license or a vSphere Enterprise Plus license is required to support continuous replication.

If you are upgrading or uninstalling a VAIO filter and you have a Standard license, you must either suspend or manually power off VMs because their ESX hosts will enter maintenance mode during the upgrade or uninstall process. If you are upgrading or uninstalling a VAIO filter and you have a vSphere Enterprise Plus license, VMware DRS automatically moves the VMs to active ESX hosts using vMotion, while the VAIO filter is being upgraded or uninstalled on the other ESX host to ensure that there is no downtime for the VMs.


  • Continuous replication using VAIO is not supported for clusters that have different versions of ESXi. For more information, go to Install I/O Filters in a Cluster on the VMware documentation website.

  • VAIO support is available only for VMware versions which are under the active supported products in the VMware product lifecycle matrix.


  • Two access nodes (VSA proxies): One at the source site and one at the destination site.
  • MediaAgent should be present on the destination access node.
  • Low latency network between the access nodes, preferably 10 GB ethernet, depending onI/O loads.
  • The destination requires a fast storage connection to the Recovery Point Store (RP Store).

Virtual Machine Disks

Before configuring a source VM for continuous replication, ensure that the VM storage policy in vSphere is set to Datastore Default for all disks.

Access Node

You can deploy access nodes (VSA proxies) on physical or virtual machines.


  • VSA Guest Customization

Operating Systems

You can install access nodes on Windows or Linux.


  • Microsoft Windows Server 2022
  • Microsoft Windows Server 2019
  • Microsoft Windows Server 2016
  • Microsoft Windows Server 2012 R2 x64 Editions
  • Microsoft Windows Server 2012 x64 Editions


  • Install the Virtual Server Agent on a Linux machine that runs any of the following operating systems:

  • CentOS version 7.4, 7.5, 7.6, 7.7, 7.8, or 7.9

  • Oracle Linux version 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, or 9.x
  • RHEL versions 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, or 9.x

  • RHEL version 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, or 9.x


  • For RHEL/OEL 9.0 and 9.1 VSA access nodes, if the the and VDDK 8.0.1 load fails, upgrade openssl-libs to the latest version to use VDDK 8.0.1. Upgrading will protect the VMware workloads.

  • To use a machine that runs RHEL 7.7 as a VSA proxy, you must install the pcre-devel-8.32-17.el7.x86_64 package.

  • For Oracle Linux 8.x or 9.x or RHEL 8.x or 9.x VMs, to install operating system packages that are required to enable automatic installation of Mono, register the VMs with Oracle Linux or Red Hat.

For more information, see Deploying a CentOS or RHEL Machine as a VSA Proxy.

Plug-In Installation or Upgrade Requirements

  • VAIO plug-in 1.36.1
  • Ensure that vCenter permissions are configured correctly as described in Permissions for Custom User Accounts.

  • The VMware vCenter Server user account used to install plug-ins must have administrator privileges for installation or upgrade.

  • For each ESX host, the acceptance level can be one of the following:

    • VMwareAccepted
    • PartnerSupported
    • CommunitySupported
  • Plug-ins must be part of protected and replicated data centers (ESX clusters).

  • vCLS VMs running from versions 7.0u1 and up need to be on a cluster datastore so that installation of the plugin can succeed.
  • To use a Linux access node, manually create the head and tail storage policies.

Source Access Node Cache Requirement

Cache location: Job Results directory

Network Bandwidth

Provide network bandwidth based on the estimated I/O speed. For example:

  • Protected VMs: 10
  • Rate at which each VM performs I/O: 100 MB/s
  • Preferred Network Speed: 8000 Mbps

Preferred Recovery Point Store (RP Store) Requirement

Size the RP Store based on I/O throughput and RP Retention criteria. For example:

  • RP Store I/O throughput: 100 MB/s
  • Total Retention Time (hours): 5 Hrs
  • RP Store size: 1800000 MB (1.72 TB)

Firewall Port Requirements

For environments that include a firewall, open the following ports:

  • For ESXi servers on the source site, open port 33040.
  • For ESXi servers on the destination site, open port 33041.

These ports are used by the BLR service to communicate with VAIO daemons.