Virtualization and Cloud Recommendations

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Virtualization and Cloud

Geo SCADA can be deployed in a virtual or Cloud environment, with one or more virtual servers running on the same physical hardware and sharing other peripheral devices. When using virtualization or cloud, there are several considerations you need to make relating to licensing, hardware and software requirements:

Licensing

To comply with Geo SCADA licensing terms, you must acquire a license for each copy of Geo SCADA that runs on a virtual or cloud server.

If you are using dongle licenses, you will need to set up a hardware 'pass-through' for the USB ports. This will allow the hardware's USB ports to be associated with the virtual servers correctly. You also need to ensure that the hardware has a sufficient number of USB ports available (one USB port per Virtual Machine running Geo SCADA is required).

If you are using soft-key license files, you should set up the virtual machine (VM) or cloud environment to use a fixed MAC Address for the virtual Ethernet card and a fixed ID for the system disk.

Licensing for multiple-server architectures (redundancy) works in the same way as non-virtualized Geo SCADA servers, with a license required for each running instance of Geo SCADA. We recommend that the Main server in a multiple-server architecture is located on different virtual hardware or cloud location to the Standby server(s), as this will allow for redundancy in the event of a hardware failure.

Hardware Requirements

You need to make sure that the hardware that runs the servers has sufficient:

• Disk space
• RAM and processor cores
• Disk performance.

Each virtual or cloud server requires the same resources as a non-virtualized Geo SCADA server (see Recommended Server Configurations). So the hardware that is running the servers needs to have sufficient resources for all of the servers combined. For example, if the hardware is running two Geo SCADA servers, one with 10,000 database objects and one with 50,000 database objects, you would need to calculate:

• The requirements for the server with 10,000 database objects, plus
• The requirements for the server with 50,000 database objects.

The hardware needs at least the combined total resources required by the virtual servers.

The minimum requirements defined above are those required by Geo SCADA in a virtual server or cloud environment. Where possible Geo SCADA should have exclusive use of memory, CPU and disk bandwidth. Virtual servers introduce overheads, therefore the minimum requirements for the virtual server technology may be greater than the recommended Geo SCADA hardware requirements. For more information, please refer to the documentation for your virtual server solution.

When using virtualization and cloud, you also need to consider disk access for the virtual servers. Performance can be affected by multiple servers attempting to access the same disk at the same time, or disks connected to the servers with a slower technology than usually available with physical servers. So where possible, you should use separate disks to distribute load appropriately, and select disk types and attributes for performance.

Geo SCADA maximizes the use of memory buffering to reduce the impact of delayed disk access to a minimum. For example, most disk write operations are not carried out under a database lock. However, there are some unavoidable situations where the server requires disk access before further operations can proceed, and for this reason we recommend SSD drives or magnetic disks with good cache sizes. It is not possible to advise specifically as the performance of each system will vary widely.

It's important to note that servers used for Geo SCADA and other SCADA processes need real-time performance rather than typical IT servers which have more relaxed response time requirements. For example, compare a mimic taking an extra few seconds to load may have a higher user and system impact compared to an Excel file taking an extra few seconds to load. If there is competition for shared resources across multiple servers then the performance of Geo SCADA will degrade.

Software Requirements and Support

Many Geo SCADA customers have successfully deployed virtualized solutions on Microsoft Hyper-V, VMWare V-Sphere, Citrix XenServer, Oracle Virtual Box, as well as cloud deployments on Amazon Web Services, Microsoft Azure and others. The Geo SCADA Product team confirm that Geo SCADA is supported for virtualized and cloud environments to the same extent as for physical environments. 

Please note that Schneider Electric Geo SCADA Support can provide only general guidance to setting up each virtualized or cloud system.

Snapshots

Note that Virtual Machines can be snapshotted while running to create a in-motion backup. When actioned a snapshot may pause a server's operation. Geo SCADA Expert is not designed to operate with such pauses, as the real-time behavior can be disrupted and the driver, database and client operations can time out and cause issues. It is difficult to state how long such an interruption needs to be before causing problems.

Further Recommendations

We recommend the following Geo SCADA Resource Center sections for additional guidance:

Network: Network Configuration and Performance

CPU and Memory: CPU and Memory Performance

Storage: Hard Disk Configuration and Performance

Storage Area Networks (SAN): SAN Recommendations

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