Solution description


The solution consists of server and client parts. The server one contains components, which are installed on the backup DC and responsible for retrieving changes from customer devices, their deduplication, storing data and failover as well in case of disaster. The server part also includes storage - an object storage located in the backup data center where full and incremental replications of customer machines are saved.


As for the client part, it includes agents installed on VMware vSphere for replication of machines on the cloud platform or agents for Windows/Linux installed on guest operating systems for replication of other types of cloud platforms and physical machines.

Client for VMware (VMware agent) - a Linux machine, supplied as an OVA file, that is deployed to each ESXi host and that replicates machines on these hosts. Standard VMware tools are used to detect changes and obtain deltas on the machines (Changed Block Tracking API), which in turn induce the tools of operating systems (quiesce) to preserve data consistency inside replicas.

Linux agent - a Linux daemon installed on a guest OS in case of replicating machines on public clouds like AWS, Microsoft Azure or Google Cloud as well as Hyper-V, KVM, OpenStack or physical machines with Linux operating systems. Supplied as a bash instruction to be executed in guest operating system terminal, thereby the agent is installed on the machine.

Windows agent - a Windows service installed on a guest OS in case of replicating machines on public clouds like Microsoft Azure or Google Cloud as well as Hyper-V, KVM, OpenStack or physical machines with Windows operating systems. Supplied as a ZIP file with MSI and a configuration file for installation on a guest operating system.


In case of a VMware infrastructure replication, there is no need to install Windows/Linux agents on each machine. Just install a VMware agent on each ESXi host of vSphere.

Acura compatibility matrix and supported systems

Source Platform Platform/OS version Agent, replication type, distribution

VMware ESXi



ESXi 5.5+

HVRAgent (VMware)

external replication

OVA VM template

Bare Metal




Oracle Cloud

Windows 7

HWRAgent (Windows)

internal replication

MSI installer

Windows 8
Windows 10
Windows Server 2008R2
Windows Server 2012
Windows Server 2012R2
Windows Server 2016
Debian 7

HLRAgent (Linux)

internal replication

.deb/.rpm packages

Debian 8
Uubntu 14.04
Ubuntu 16.04
Ubuntu 18.04
RHEL/CentOS 6.5+
RHEL/CentOS 7.1+

OS upgrade to the latest Service Pack and patches is recommended.

Linux kernel support for HLRAgent

RHEL/CentOS 6.x versions:


32-bit systems are not supported

  • 2.6.32-220.el6.x86_64
  • 2.6.32-358.el6.x86_64
  • 2.6.32-431.el6.x86_64
  • 2.6.32-573.el6.x86_64
  • 2.6.32-642.el6.x86_64
  • 2.6.32-696.el6.x86_64
  • 2.6.32-754.el6.x86_64

RHEL/CentOS 7.x versions:

  • 3.10.0-123.el7.x86_64
  • 3.10.0-229.el7.x86_64
  • 3.10.0-327.el7.x86_64
  • 3.10.0-693.el7.x86_64
  • 3.10.0-862.el7.x86_64
  • 3.10.0-957.el7.x86_64
  • 3.10.0-1062.el7.x86_64
  • 3.10.0-1127.el7.x86_64

RHEL/CentOS 8.x versions:

  • 4.18.0-147.el8.x86_64
  • 4.18.0-193.el8.x86_64

Ubuntu versions: 14.04, 16.04, 18.04, 20.04


Please contact Hystax Support team at if the required kernel is not in the list above.

Hystax Acura Limitations

  1. Virtual machines with disks engaged in SCSI bus sharing are not supported because VMware does not support snapshotting such VMs.
  2. RDM virtual disks in physical mode, Independent disks, and disks connected via in-guest iSCSI initiator are not supported. Network shares and mount points targeted to 3rd party storage devices are also skipped, as these volumes/disks are not visible in the VM configuration file.
  3. Free ESXi is not supported. Hystax Acura leverages vSphere and vStorage APIs that are disabled by VMware in free ESXi.
  4. Hystax Windows Replication Agent supports only NTFS filesystems.
  5. Hystax Windows Replication Agent doesn’t support extended volumes.
  6. Hystax Windows Replication Agent converts dynamic disks to basic ones while protecting them.
  7. Hystax Linux Replication Agent supports replication of machines with up to 64 disks.
  8. Windows servers with the enabled Storage Replica feature are not supported.

AWS Limitations

Hystax Acura uses an import image mechanism to launch replicated machines on AWS, therefore all “Import Image” limitations apply. Refer to the official AWS documentation for more details.

Azure Limitations

VMware Limitations

  • Max number of restore points stored for one machine is 29.
  • Replication and failover of the same machine can’t be started at the same time because both processes work with the same machine on the target side.

Release notes

  • Consistent replication of VMware workloads by external agents
  • Consistent replication of Hyper-V, KVM, Bare Metal and public cloud workloads by internal agents
  • Spin up of replicated workloads on KVM-based platforms
  • Data deduplication and WAN-optimization
  • Failback of workloads to production workloads on Amazon Web Services
  • Various types of reports
  • System events and notifications
  • Granular user and roles management