Freelance virtualised: How (available) would you like it?
Whether replacing dozens of process stations with a redundant server environment with central management or clear monitoring while simultaneously increasing availability: there are many reasons why virtualising an ABB Freelance system is worthwhile. We show you what options are available to you and why a Freelance upgrade to version 2019 is recommended in the course of virtualisation.
About ten years after a wave of virtualization swept through and revolutionized office IT, it is now rightly spreading to the OTWhat is OT?OT (Operational Technology) encompasses hardware and software used to monitor and control devices, processes, and events, as well as to detect changes., i.e., automation systems. The advantages are obvious. A large number of systems, such as engineering and operator stations, can be centrally managed within a server structure as VMWhat is a VM?A VM (virtual machine) is a software-based computer. It allows multiple operating systems to run simultaneously on a single piece of physical hardware and efficiently pool resources. can be executed in a hardware-independent and efficient manner. Advantages:
• Centralized management
• Less maintenance
• More efficient use of hardware
• Hardware replacement without downtime
• Centralized backup solution
• Engineering and test environments that can be set up very quickly
Freelance + Virtualisation = Freedom
The Process control systemWhat is a process control system?Process control systems are used to manage technical processes. They enable the monitoring, control, and regulation of process-related equipment. "Freelance" is still worth recommending. It is relatively simple and very robust, and serves its purpose well as a central control layer for distributed systems. One minor drawback is the lack of redundancy on PCWhat is a PC?A PC (personal computer) is a computer designed for personal use. Level – however, this can be virtually eliminated when combined with virtualization. Which is better?
Over the past 30 years, CTE has had the opportunity to SCADAWhat is SCADA?SCADA (Supervisory Control and Data Acquisition) is a hardware and software system designed for real-time control. It collects process data to provide a centralized view of operational processes. and design, plan, and implement control systems. Products from Siemens, ABB, Emerson, GE Fanuc, Rockwell, and Copa-Data were used in these projects. More important than the question of whether one is better than the other is what the requirements are and how the system can be planned and implemented. Even the best control system can end up in a confusing mess due to improper planning. On the other hand, a well-structured SCADA project can offer a customer and their facility exactly what is needed.
Variants of the cluster structure
To run the system in a fail-safe manner, you need High Availability Cluster (HA Cluster)What is a high-availability cluster?An HA cluster is a group of servers that work together to keep virtual systems available even if one server fails.Whether it’s “VMware vSphere” or “Microsoft Hyper-V,” both vendors support the key features of a cluster: HA, live migration, and automatic load balancing. In an HA cluster, virtualized systems are not run simultaneously on both hosts; instead, if one host fails, they are restarted on another available host. Restarting the machine results in a brief outage lasting just a few seconds. Although it is also possible to run a VM on two hosts simultaneously, as Fault Tolerant (FT)What is a Fault Tolerant (FT)?A fault-tolerant system ensures the availability of virtual machines (VMs) by having a second VM mirror the state of the primary VM in real time and take over immediately in the event of a failure.However, this solution involves high hardware and licensing costs on the one hand, and on the other hand, it does not protect against system failures. Therefore, it is rarely recommended from a cost-benefit perspective.
Quite traditional
The minimum solution for an HA cluster consists of two hosts and a central storage (see Fig. 1). In the best case scenario, the storage hardware is designed to be completely redundant so that if a component fails, the VMs on the hosts can continue to run. With this variant, one cluster host is allowed to fail and the VMs are restarted on the second host. However, if the shared storage fails completely, VMs can no longer run on the hosts.
Even smarter
Another variant is a modern hyperconverged HA cluster, which no longer uses traditional storage, but combines the local disk in the individual hosts into a logical volume with the desired reliability (see Fig. 2). A major advantage of this solution is that the entire central storage can be dispensed with. Thanks to the local disks in the hosts, there is no longer a "single point of failure". One component can fail completely, regardless of which one. However, this variant requires at least three hosts and a 10G network.
Even more independent
The premium version with full site redundancy consists of a hyperconverged HA cluster with at least four hosts. The failure of a single host or even an entire site is automatically intercepted by the cluster and the VMs are available again within a short period of time. Central and cross-location services can thus be provided regardless of location. At the same time, the VMs can be brought close to their assigned field components in order to create cells that are more independent of external circumstances.
However, PLEASE NOTE!
Clustering 'only' protects against the failure of individual hardware components, but not against software problems. Targeted monitoring of the relevant systems is therefore important for such infrastructures, in order to provide immediate alerts in the event of redundancy failures and to proactively counteract problems that can be identified in good time. Clustering also fails to protect against changes like reconfiguration, deletion, or encryption within a VM. However, the cluster consistently manages these actions across all instances. A professional backup solution is therefore always worth its weight in gold.
CONCLUSION - When is something worthwhile?
Despite all the advantages, virtualisation is often a question of cost. If many operator stations can be replaced, the acquisition costs of the server structure are already lower than the costs of the individual hardware. However, if the reduced maintenance costs and higher availability are also taken into account, the decision is often made in favour of virtualisation even if the hardware costs are somewhat higher. When replacing a small number of clients, we believe it should be carefully considered whether virtualisation is worthwhile. After all, the greater complexity of the system landscape should not be underestimated. Unless the servers already exist or are to be used for additional tasks. It's up to you to decide which option to choose.
Combination with Freelance Upgrade
In addition to new hardware and optimised user operation, Freelance 2019 offers two new features in particular, which can be very helpful. Firstly, up to four monitors per operating station are now supported and secondly - particularly useful in connection with virtualisation - the user administration can be connected to the Windows domain controller.
