Frequently Asked Questions (FAQ)

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What did Stratus recently announce?

Stratus announced on December 7 the general availability of a new software update for its ztC Edge computing product line. Stratus Redundant Linux version 2.2 offers customers an enhanced REST API, new security patches, and one-click enablement for a new, web-based systems management tool – ztC Advisor. Current customers are encouraged to upgrade to this latest version, to take advantage of these new features and enhancements.

Why are these new features and enhancements important?

With SRL 2.2, improvements in interoperability, security and manageability help customers further reduce their cost of operation and maintenance, improve productivity, and minimize risk. An enhanced REST API, with more granular information at the VM level, enables admins to better optimize application performance and resource utilization. SRL 2.2 incorporates Stratus’s latest security patches and updates, addressing nearly 200 known vulnerabilities and bugs to deliver a more secure, reliable operating platform for its ztC Edge solutions. Lastly, one-click enablement for ztC Advisor, a new web-based systems management tool, enables admins of all backgrounds that need to centrally manage multiple ztC Edge platforms and ensure their availability, become productive faster.

What is Stratus’s ztC Edge solution?

Stratus ztC Edge is a secure, rugged, highly automated computing platform that helps understaffed organizations improve productivity, increase operational efficiency, and reduce downtime risk at the edge. “ztC” stands for “zero touch computing”. With its built-in virtualization, automated protection, industrial interoperability, OT manageability, and field serviceability, ztC Edge delivers highly available virtualized edge applications quickly and easily.

Who is the ztC Edge for, and what are its main benefits?

The solution is designed for both Operations and IT staff that need to quickly deliver reliable edge and IoT (Internet of Things) applications in remote, resource constrained environments. Its primary benefit is greater productivity through increased resource utilization, improved operational efficiency, and reduced downtime.

Where can I get ztC Edge? In what are the specific countries and languages is it currently supported?

ztC Edge is supported globally and localized into most major Tier 1 languages. For a current list of supported languages and countries, please visit our localization status page.

Which product safety and quality certifications does ztC Edge comply with or adhere to?

Stratus ztC Edge is currently certified under most global programs, like FCC, CE, VCCI, CCC, and others. The ztC Edge 110i model is Class I Division 2 (CI D2) certified, ensuring that it can be safely deployed in potentially hazardous environments with an approved enclosure. For a current list of environmental certifications, please visit our certification status page.

What are Stratus ztC Edge’s key features?

Its key features are its built-in virtualization, simplified security,  industrial interoperability, OT manageability, rugged redundant nodes, automated protection, field serviceability, and optional and managed support services. Differentiated from other edge computing platforms by its operational simplicity and ease of use, the level of protection it provides, and its breadth of automated capabilities, ztC Edge helps both OT and IT staff deliver highly reliable virtualized edge applications quickly and easily, allowing understaffed organizations to increase productivity and efficiency, while lowering downtime risk. For more information about ztC Edge, please visit the ztC Edge product homepage on, or download and read the ztC Edge data sheet.

What applications do companies typically run on ztC Edge?

Stratus ztC Edge is designed to deliver highly reliable edge computing applications quickly and easily, such as industrial control applications (e.g. SCADA/HMI, historian) from Rockwell, Aveva (Wonderware), GE, and Inductive Automation, and building management systems from companies like Schneider Electric and Gallagher. It can also support many other emerging edge applications – ThinManager remote desktop virtualization software from Rockwell, analytics frameworks like FogHorn’s Lightning EdgeML.

Can ztC Edge be ordered, or customized with different processors, memory, and storage?

Yes and no. Stratus offers two different hardware models – the ztC Edge 100i and ztC Edge 110i – with different processor, storage, and networking capacities. But the models themselves are not further customizable. Fixed configurations, and a minimum set of product SKUs simplify order entry and fulfillment. The platforms are available as single node versions, for customers that don’t immediately require a highly available or fault tolerant computing platform, or for those that want to add redundancy later. Redundant systems are also available for purchase. For a summary of the similarities and differences between the two hardware models, please visit the ztC Edge product homepage on, or download and read the ztC Edge data sheet.

What are the Windows licensing requirements for ztC Edge if I want to run Windows guest operating systems on them?

Stratus ztC Edge requires at least one Windows license, which will support up to 2 VMs. For a redundant deployment, you will need to acquire two Windows licenses (one for each ztC Edge node) at a minimum. The two licenses will provide support for up to four VMs on a redundant ztC Edge system. If customers want to run 5 to 8 small VMs on a redundant ztC Edge system, they will need to acquire two more Windows licenses (one more for each node).

Are current ztC Edge customers entitled to Stratus Redundant Linux version 2.2?

Yes, if they have an active support contract. Current ztC Edge customers running Stratus Redundant Linux (SRL) versions 1.x or 2.x that also have an active System Support or System Health subscription are entitled to download, upgrade, and use SRL 2.2 for no additional cost. Their support subscription entitles them to software patches and upgrades. Customers that are running SRL 2.1 can use the easy upgrade feature available in their ztC Edge Console to upgrade their system. Customers that are running any earlier version of SRL (e.g. version 1.x) should contact Stratus Support to confirm their upgrade process.

Earlier you mentioned that customers with active support contracts can upgrade to SRL 2.2, as well as register to use ztC Advisor, for no additional charge. What are the support contract options that are available with ztC Edge?

Stratus offers two annual (and renewable) support options – System Support and System Health – to help customers maximize their ztC Edge return on investment.

Customers subscribing to System Support services receive 24×7 web and phone-based technical support services with a 30-minute response SLA for critical issues. They also receive root cause problem determination services, access to patches, updates, knowledgebase, and other resources through a secure, self-service portal, and 3-day advance parts exchange. Unlike a warranty parts replacement, Stratus ships to customers replacement nodes before receiving a node in exchange.

Customers subscribing to System Health services receive 24×7 system monitoring, alert triage, system log reviews, predictive failure analysis, and media retention services. System Health services are more proactive in nature and designed to identify and fix issues before they become more serious problems. System Health is an add on subscription service to System Support.

You mentioned that Stratus Redundant Linux includes its own virtualization platform. On what technology is the virtualization platform based?

The system software for ztC Edge, Stratus Redundant Linux, is based in part on the CentOS distribution and KVM hypervisor. Although it is based on open source software, it has been customized by Stratus. For this reason, customers wanting to update their systems should only apply patches that they’ve received from Stratus. The addition of an availability layer, along with a management tool, the ztC Edge Console, enables the management of an individual system and its VMs.

What operating systems are supported for virtual guests?

ztC Edge supports most major Windows and Linux operating systems as virtual guests. For a current list of supported guest operating systems, please visit our guest OS support status page.

What is the capacity of a ztC Edge solution? How many applications can you run on it simultaneously?

The number of applications that can simultaneously be operated on ztC Edge depends on several factors, including the application’s resource requirements, its performance expectations, and desired availability level.

For example, a single Stratus ztC Edge platform can be set up to support three moderately sized VMs and deliver acceptable performance when configured using a SCADA application’s default settings. For example, each 100i node comes with 4 Intel i7 hyperthreaded cores (which translates into 8 virtual CPUs), 32 GB of memory, and 512 GB of SSD storage. The ztC Edge operating system itself requires 2 virtual CPUs, 2 GB of RAM, and about 20% of the available application memory and storage if deployed in redundant mode. A redundant ztC Edge 100i system might be configured with 3 VMs, each sized with 2 virtual CPUs and 8 GB of RAM. One VM with 60 GB of storage might be used for a 10,000 tag SCADA/HMI workload, with data being collected at 1 tag/sec. The second VM with 250 GB of storage would support a 10,000 tag local Historian, at default compression. The third VM with 90 GB of disk would be used to run remote desktop services, supporting 3 concurrent users or sessions.

For more information about your specific use case, or for the latest sizing guides, please contact your local Stratus partner or customer success engineer.

Are 3 VMs the maximum number ztC Edge will support?

No. The total number of VMs that are supported depends on the applications that are running, as well as your performance requirements. ztC Edge has been designed, however, to support 3 VMs in a typical edge computing environment. If a customer is running more lightweight VM use cases, then more than 3 VMs are possible.

Can the hypervisor in Stratus Redundant Linux use unmodified VMware images?

Yes. Virtual appliances (pre-configured virtual machine images) in both OVF and OVA formats are supported by ztC Edge’s virtualization host, including those templates formatted for VMware. When VMware images, including UEFI VMs (unified extensible firmware interface) are retrieved using ztC Edge’s management tool (ztC Edge Console), they are automatically imported into the format required for ztC Edge and then started.

Is ztC Edge a fault tolerant solution?

Yes, it can be. Redundant ztC Edge 110i systems can be configured to support fault tolerant (FT) or highly available (HA) workloads, at the VM level. In fact, customers can run FT and HA workloads simultaneously, on the same redundant 110i system, as long as they are on different VMs. This flexibility allows customers to match the level of availability to the criticality of their workloads and optimize resource utilization.

ztC Edge 100i models support HA workloads (when deployed as a redundant system), but they don’t support fault tolerant workloads. This is because the 10 GbE interconnects required for fault tolerance are only available with 110i hardware.

Does Stratus offer other fault tolerant solutions? What are the similarities and differences between ftServer and ztC Edge?

Yes, Stratus offers another fault tolerant solution called ftServer. In fact, the “ft” in “ftServer” stands for “fault tolerant”.

ztC Edge is purpose-built for Edge environments and well suited for moderately-sized edge applications. Its compact, rugged form factor allows it to be deployed right on the plant floor — on a wall, DIN rail, cabinet, control panel, or piece of production equipment. ztC Edge comfortably supports the visualization and control of environments with up to 10,000 tags and 3 concurrent users.

ftServer is designed for larger industrial control applications, and the greater capacity of its 4U rack mount form factor plus its support for third-party virtualization platforms and mass storage options makes it better suited for larger mission critical workloads deployed in regional data centers or edge control rooms.

Do the two ztC Edge nodes running in fault tolerant mode act like a single logical system (like ftServer) or is one a primary and the other a standby?

ztC Edge implements fault tolerance differently than ftServer. ztC Edge uses a software-based approach, with checkpointing, while ftServer uses a hardware based approach, with FPGAs.

When operating in fault tolerant mode, the two nodes in a ztC Edge solution act like a redundant system, continually replicating all data written to disk, all data in memory, and all CPU states, across both nodes so that in the event of a catastrophic failure in one node, VMs can resume on the other surviving node exactly where the first node left off. The second node is in an “active standby”, or “ready” mode, continually being updated and ready to take over should the need arise. There may be a brief delay (up to five seconds) while the second node takes over, but no data or transactions are lost.

On the other hand, ftServer systems duplicate all processing and I/O across both of its subsystems simultaneously. In essence, there are two computers doing the exact same thing at the exact same time, both acting as primary servers. If one of the subsystems fails, the remaining one continues to act as the primary server – only now by itself. There is no delay, since one subsystem is not “taking over” for another subsystem.

Are there any conditions associated with, or limitations of the automated local site recovery feature in ztC Edge?

The two nodes in a redundant ztC Edge system can be deployed in different physical locations, as long as the round trip latency in the network connectivity (a-links) between the nodes is below a 10 ms threshold for highly available workloads, and 2 ms for fault tolerant workloads. Meeting these conditions enables ztC Edge to deliver local site, or metro-area disaster recovery services. Stratus recommends that for nodes separated by more than 10 meters (or 33 feet), or for nodes bridged with external switches, a quorum service also be implemented.

I know Stratus also offers a software availability product called everRun. Is Stratus ztC Edge just everRun software running on an industrial PC?

No. Stratus ztC Edge, while it does leverage technology that is also in everRun, is a different solution. Both everRun and Stratus Redundant Linux (the OS in Stratus ztC Edge) utilize the same virtualization framework and availability layer. However, Stratus Redundant Linux further exposes features in ztC Edge hardware to offer dramatically simplified deployment, and more advanced, comprehensive system monitoring and management capabilities – more than that provided by the combination of everRun on industry standard hardware alone.

How rugged are ztC Edge’s nodes? What is their IP rating? What is their recommended operating temperature, and does this change with changes in altitude?

ztC Edge is IP40 rated, and features a durable, fan-less, solid state design with no moving parts. The ztC Edge 100i model can operate in temperatures ranging from -40 to 60 °C (-40 to 140 °F), when using DC power. The ztC Edge 110i model can operate in temperatures ranging from -20 to 55 °C (-4 to 131 °F), when using DC power. If the AC power supplies that are provided with the systems are used instead, the recommended operating temperature range changes to 0 to 50 °C (32 to 122 °F) for both models.

At higher altitudes, air is thinner and typically drier, which results in lower heat dissipation through air convection. As a result, the recommended operating temperature range at higher altitudes is reduced, because ztC Edge is a fan-less, convection cooled product. For example, at an altitude of 4200 meters (14,000 feet), the maximum ambient temperature should be kept below 35 °C (95 °F). For the recommended temperature ranges or ratings for your specific use case, please contact Stratus.

Does ztC Edge support Power over Ethernet? What is its inrush current?

No, ztC Edge does not currently support PoE. The maximum inrush current for both ztC Edge 100i and 110i systems is 20A. For additional technical specifications, please visit the ztC Edge product homepage on

How does IP addressing work with ztC Edge?

Each node in a redundant ztC Edge system has its own IP address, as does the system itself and each VM. Applications typically reside in VMs. Communications are handled by the system, with routing taking place to the VMs transparently, regardless of which node they are currently running on.

What is ztC Advisor?

ztC Advisor is a new web-based edge systems management tool that makes it easier for administrators of all backgrounds – Operations and IT – to remotely manage their ztC Edge computing infrastructure at scale. ztC Advisor simplifies the remote, centralized monitoring and management of multiple ztC Edge platforms. Through a secure, web based portal, customers can quickly and easily view the health and utilization of their entire ztC Edge inventory, helping them remotely triage issue, improve productivity, and mitigate risk. Starting Dec 7, ztC Advisor will be offered to Stratus customers as a preview product. More information is available at

What does it mean that ztC Advisor is being offered as a “preview” product?

In order to gather information about this new product, ztC Advisor is initially being offered to current customers as a free preview. For a limited time, current customers with active support and maintenance contracts will be able to register to use ztC Advisor for no additional cost, in exchange for providing Stratus feedback about their experience. All new customers purchasing ztC Edge platforms are encouraged to register and try ztC Advisor. All current customers using ztC Edge platforms running SRL 2.1 (or earlier) are encouraged to update their systems to SRL 2.2 and take advantage of this new offering.

How do I access ztC Advisor? Do I need to log into my ztC Edge dashboard first?

To access ztC Advisor, just enter your support portal credentials at If you don’t have a user id and password (or forgot what they were), you can create (or retrieve) them at this same site.

I have a Stratus Support account, but I forgot my password. Can I retrieve or reset it?

You can use the “reset password” function on the ztC Advisor login page to reset your password. This will enable you to set a new password that can be used for BOTH Stratus support portal AND ztC Advisor access.

How do I get my ztC Edge platforms to show up in ztC Advisor?

Stratus will automatically populate your ztC Advisor dashboard with any ztC Edge platforms that you own, once you log in.

I see my ztC Edge systems, but they are all categorized as “Not Provisioned” - what does this means?

ztC Edge platforms will appear in this “Not Provisioned” state until they are registered. Once you register your platforms and enable ztC Advisor in each ztC Edge console, they will show up in a different state in the dashboard.

Do I need to install an agent or special software in ztC Edge for it to appear in the ztC Advisor portal?

No, there is no separate software to install or manage on your ztC Edge system. However, your ztC Edge platform does need to be running SRL version 2.2 or higher to be able to report platform data to ztC Advisor. In addition, there is a simple enable/disable switch within your ztC Edge’s Preferences section to enable the visibility of system data.

What is Stratus everRun?

everRun is a highly versatile software platform that delivers instant protection for your applications and data. Highly customizable, and compatible with a wide range of industry standard computing hardware, this operating environment is easily embedded into third party solutions that require greater reliability. More information is available at

Who is everRun for, and what are its main benefits?

everRun is suitable for a wide range of enterprise data center IT and edge OT use cases, but it is particularly beneficial to value-added resellers and machine builders that desire incorporating more reliable computing infrastructure into their infrastructure solutions and production equipment. Using everRun helps companies maximize their return on investment, speed time to market, and lower their risk of unplanned downtime.

What are everRun’s key features?

everRun’s key features include its built-in virtualization host, customizable availability levels, metro-wide area protection, and industry-standard hardware and software support. Based on KVM, everRun’s hypervisor supports most Windows and Linux guest operating systems. Customers can choose the level of availability that they need – high availability or fault tolerance – for the workloads running on each virtual machine. everRun can be deployed in a metro-area configuration, to support local-area disaster recovery, and is compatible with a wide variety of Intel x86-based systems.

What applications do companies typically run on everRun?

Companies run a wide variety of applications on everRun based solutions – anywhere higher availability is needed – and needed quickly and easily. Typical use cases include building management, energy management and security systems, public safety systems, retail POS, and manufacturing and logistics applications. For more information about Stratus customers that are lowering their downtime risk with everRun, please visit

Which versions of everRun are currently being sold and supported? What is your most recent release?

everRun 7.8 is our newest product, and it was released on Dec. 4, 2020. When a new everRun version is released, older versions are typically no longer sold. But these older version continue to be supported for several years after their final end of sale date, either fully, or in a limited “best efforts” capacity. Currently, full support is being offered to customers using everRun 7.8, 7.7, 7.6 and 7.5. Limited support is available for customers using everRun 7.4 and earlier, as well as version 6.2 and higher. For more information about everRun’s support lifecycle, please visit

If I’m currently using an older version of everRun, can I download and use the most recent release?

Yes, as long as you have an active support contract. Current customers using everRun 7.7 or earlier that also have an active support subscription, are entitled to download, upgrade, and use everRun 7.8 for no additional cost. Their support subscription entitles them to free software patches and updates. Current and previous everRun releases, as well as documentation and tools, are available and can be downloaded from

Is there a free version of everRun available that I can try before I buy?

Yes. Stratus encourages prospects to try everRun and experience for themselves its many value-added features. You can start your risk-free 30-day trial by filling out the form available at

You mentioned that everRun has a built-in virtualization platform. On what technology is this virtualization platform based?

everRun’s virtualization host is based on the open source KVM hypervisor. everRun also includes open source packages from the CentOS distribution, as well as technology developed and hardened by Stratus. For this reason, customers updating their systems should only apply patches that they’ve received from Stratus. everRun ships with its own administrative console and tools for managing its virtual machines.

What operating systems are supported as virtual guests on this platform?

everRun supports most major Windows and Linux operating systems as virtual guests. For a current list of supported guest operating systems, please visit our guest OS support status page.

Can everRun’s hypervisor use unmodified VMware images?

Yes. Virtual appliances (pre-configured virtual machine images) in both OVF and OVA formats are supported by everRun’s virtualization host, including those templates formatted for VMware. When VMware images, including UEFI VMs (unified extensible firmware interface) are retrieved using everRun’s management console, they are automatically imported into the format required for everRun and then started. For more information about how to do this, please see the Managing Virtual Machines section of the everRun User Guide.

What hardware systems can everRun be installed on? Are there any limitations?

everRun is supported on a wide variety of Intel-based x86 servers and workstations. For a complete list, please, visit the supported hardware page.

You mentioned that when applications run on everRun-based systems, they become highly available. Is everRun a fault tolerant solution?

Yes, it can be. everRun-based systems can be customized to deliver fault tolerant (FT) workloads, highly available (HA) workloads, or a combination of both. Customers can run FT and HA workloads simultaneously, on the same everRun system, as long as they are on different VMs, and other conditions are met. This flexibility allows customers to match the level of availability to the criticality of their workloads and optimize resource utilization. For a more detailed explanation of the resource requirements for the different availability levels, please visit the Systems Requirements section of the everRun User Guide.

Does Stratus offer other fault tolerant solutions? What are the similarities and differences between everRun and ztC Edge or ftServer?

Yes, Stratus’s portfolio includes other highly available and fault tolerant platforms, including ztC Edge and ftServer. everRun is a software solution, that when combined with industry standard computing hardware, allows you to customize your workload protection.

ztC Edge is purpose-built solution that combines hardware, software, and services. Designed specifically for Edge environments, it’s well suited for moderately-sized edge applications. Its compact, rugged form factor allows it to be deployed directly on the plant floor — on a wall, DIN rail, cabinet, control panel, or piece of production equipment. For example, ztC Edge can comfortably support visualization and control environments with up to 10,000 tags and 3 concurrent users.

ftServer is designed for larger mission-critical edge applications.  In fact, the “ft” in “ftServer” stands for “fault tolerant”. The greater capacity of its 4U rack mount form factor, plus its support for third-party virtualization platforms and mass storage options, makes it better suited for larger mission critical workloads deployed in regional data centers or edge control rooms.

What is SplitSite? Are there any requirements or conditions associated with the use of this feature in everRun?

The two computers in an everRun-based system can be deployed in different physical locations, as long as the round trip latency between them meets a 10 ms threshold for highly available workloads, and 2 ms for fault tolerant workloads. As long as these conditions are met, the deployment of the individual computers can be “split” within a local “site” to deliver local-area, or metro-area disaster recovery services. Stratus recommends that for computers separated by more than 10 meters (or 33 feet), or for servers bridged with external switches, a quorum service also be implemented. More detailed information about SplitSite configurations can be found in the everRun User Guide.

Where can I get more information about everRun?

More information about everRun can be found on the everRun product homepage on More detailed technical information about its resource and configuration requirements can be found in the everRun User Guide.

What’s new or improved about the latest ftServer models? Why should I consider them?

The 11th generation ftServer platform brings new technologies and improved performance to customers. It leverages Intel Xeon Silver 4210 and Xeon Gold 5220 processors. Compared to the 10th generation ftServer, it includes a higher top-end processor core count (18), higher maximum memory (using 64 GB DIMMs, up to 1,280 GB), and higher maximum internal storage (using 2.4 TB HDDs, up to 19.2 TB). It also includes first-time ftServer support for newer technology NVMe internal drives (1.6 TB NVMe SSDs).  Based on the age of your current compute infrastructure, your availability SLAs, and the types of workloads you are running on them, these new ftServer models may be compelling platforms to easily and cost effectively meet your performance, recovery time, and recovery point objectives for your most processor-intensive and data-intensive workloads.

What operating environments does ftServer Gen 11 support?

Stratus ftServer supports industry standard operating environments, including Microsoft Windows Server, VMware vSphere, and Red Hat Enterprise Linux. ftServer Gen 11, which includes the ftServer 2910, 4910, and 6910 models, will support VMware vSphere 7.0 and Microsoft Windows Server 2019 (with ability to downgrade to Windows Server 2016). ftServer Gen 11 will also support RedHat Enterprise Linux 8 later in the calendar year.

Is ftServer a continuously available or highly available platform?

Stratus ftServer is a continuously available platform. Every single ftServer system is made up of two identical halves – two identical customer replaceable units (CRUs) – each with their own processors, memory, and storage. Identical Stratus field programmable gate arrays (FPGA) on each CRU run Lockstep firmware, ensuring the same operation takes place at the same time on each processor. If a component in one CRU fails, there’s no failing over to another system, because the other CRU continues to run without any interruption. Redundant data paths, or multi-path I/O buses, ensure data is also synchronized on both CRUs.

Is there a difference between continuous availability and high availability?

Yes, continuous availability is about proactively preventing downtime, while high availability is about reacting as quickly as possible once downtime occurs. Continuously available platforms leverage technologies like redundancy, lockstep processing, and data mirroring to mitigate the risk of component failures and ensure continuous processing, while never compromising customers’ data. Highly available platforms leverage technologies like clustering or migration, to try and quickly recover from a component failure by restarting the service in another location.

How is ftServer different from other continuously available platforms?

ftServer is differentiated by its simplicity and ease of use. ftServer is arguably the easiest continuously available platform to deploy, manage, and service. Other solutions require complex set up, integration and configuration. ftServer offers continuous availability out of the box and doesn’t require changes to ISV applications or failover scripts. It’s self-monitoring, self-alerting, self-diagnosing, and self-remediating capabilities save administrators time and effort. The two identical halves of an ftServer system are designed to be easily replaced without special tools. When a replacement CRU is reinserted into its enclosure and powered on, the system automatically resynchronizes itself. ftServer’s ease of use makes it ideal for deployment in remote locations with limited IT resources. And an added benefit of its single system image is that only one operating system license is required (unlike clustered solutions which require two or more licenses).

Is your platform expensive? Will I be able to afford ftServer?

ftServer is comparable in cost to less robust high availability solutions that require extra switches, storage, and software OS and application licenses to create a clustered system, while providing better uptime. Many of our customers tell us that they cannot “not afford” to use ftServer, given the tremendous cost they would incur were their systems to go down. Compared to your cost of downtime, ftServer can be a very cost-effective way for you to meet your recovery time and recovery point objectives. ftServer is your assurance against loss.

How long will your servers last? How long can I expect to use them?

Some of our customers are still using commercially supported and Stratus maintained ftServer systems that were purchased and initially deployed over 15 years ago. Stratus does not have a formal ftServer hardware lifecycle policy but strives to deliver customers maximum return on investment.

What is the MTBF of an ftServer?

We do not use MTBF numbers for ftServer for our projections of number of 9’s or other factors.  Stratus calculates a factor called MTBR (Meantime between repair).  The reason we use these calculations is that ftServer’s fault tolerance provides protection against failures, resulting in no downtime for your critical applications.  Meantime between repair is a calculation that estimates the average amount of time between repairs that should be assumed.

Do I have to use virtualization when using ftServer?

No. You can run your protected applications in virtual machines, but you don’t have to. ftServer ships with Microsoft Windows Server, VMware vSphere, or Red Hat Enterprise Linux. If you want to run virtualized applications, you can utilize VMware vSphere, Windows Server Hyper-V, or Red Hat Enterprise Linux with KVM as your hypervisor. If you want to run applications natively, you can install them directly on top of Windows Server or Red Hat Enterprise Linux core operating systems.

How many virtual machines can I run on ftServer?

It depends on your ftServer model and on the size / resource allocations of your virtual machines (VM). Assuming small-to-medium sized VMs (with 2 vCPUs, for example) you could reasonably support up to 10 VMs on a 2910, 20 VMs on a 4910, and 30+ VMs on a 6910. Stratus makes available sizing guides to help customers and partners estimate their resource requirements. Please contact your partner or Stratus sales representative for more details.

What is the advantage of your new NVMe storage offerings?

NVMe technology provides performance and reliability improvements that are facilitated through a new design and architecture, that really re-invents how storage is presented by embracing the use of NAND or other memory-based storage technologies. It has been designed from the ground up with an interface that does not require SAS or SATA protocols and is directly integrated to the PCIe Bus. Stratus has implemented support for NVMe in ftServer in a way that leverages most of the benefits of NVMe, while also providing flexibility that enables hybrid internal storage options. This allows the use of lower cost drives for certain workloads (such as an operating system), while allowing NVMe disk resources to be dedicated to higher class workloads where greater performance is desired.

What is the maximum amount of internal storage that ftServer can support, and what options exist if additional storage is required?

With up to 8 mirrored pairs of internal disk drives, and with the largest drive size being 2.4 TB, the maximum raw internal storage capacity for ftServer is 19.2 TB. If additional storage is required, ftServer can be interfaced to a Stratus ftScalable external storage array. The ftScalable storage system offers up to 144 disk drives, with a maximum drive size of 1.8 TB, for almost 260 TB of total raw storage.

What does it mean when you say ftServer acts as a “single integrated system”?

Each ftServer system includes two identical halves, or customer replaceable units (CRU). Each CRU has everything that you would expect from a single standalone server – power supply, motherboard, CPU, memory, disk drives, network interfaces, etc. But ftServer utilizes its Lockstep technology to provide an active / active system that looks to an operator like a single server. The operator will see only one instance of the core operating system or hypervisor, one instance of the virtual machines, one instance of the guest operating systems, one instance of the software applications, etc. With ftServer, it is not necessary to separately manage multiple independent servers or nodes. Rather, the two CRUs within ftServer are logically presented as a single active /active system that provides full fault-tolerant protection via a single system that is simple and easy to use.

What methods are available for monitoring the health of my ftServer?

ftServer supports many monitoring and management tools and methods. If your ftServer system has access to the Internet, then Stratus recommends remote monitoring via the Stratus Active Service Network (ASN). By using Stratus’s ASN and the server’s “call home” functionality, ftServer will automatically and instantly report any anomalies or issues directly to Stratus’s customer support team. The incident will be automatically logged and a customer support ticket will be immediately created to ensure the fastest path to issue resolution. If your ftServer system does NOT have access to the Internet (perhaps due to infrastructure limitations, security restrictions, etc.) then several different local monitoring methods can be used. These methods include OPC UA, SNMP, e-mail alerts, file drop-off, monitoring via a diagnostics GUI, etc. You can use these local monitoring methods to track your server’s health status, and then call Stratus customer support or use the web-based Stratus Customer Support Portal to create a support ticket if an issue arises.

What options are available for managing automated backups of VMs on a ftServer host?

ftServer supports most standard backup methods and tools. For example, VM backups can be handled via hypervisor-provided functionality (such as exporting VMs from a VMware host) or via third-party backup and recovery tools (such as Veeam, Arcserve, Zerto, etc.).

What is the typical method of integrating ftServer into an automation system?

ftServer is a rack-mounted server that is typically installed into a server room or datacenter environment. The server would be physically installed into a 19” rack enclosure and connected to redundant power supply circuits and redundant facility networks. The server room or datacenter would need to provide clean air and temperature conditioning. ftServer can also be installed into control system panels or automation racks provided that its environmental requirements can be met.

Can the processors in ftServer be changed out or upgraded at a later date?

No. The processors in each ftServer model are specifically selected and are unique to Stratus. ftServer leverages certain functionality that is provided by specific Intel Xeon processors, and as such, these processors cannot be changed out or upgraded. Since these processors cannot be swapped out in the future, it is important to consider future expansion and growth requirements in your upfront “server sizing” stage, to ensure that your server’s compute resources will be adequate for your current  workloads, as well as into the life of your project.

Can memory and storage in ftServer be upgraded at a later date?

Yes. Each ftServer model supports a range of memory and storage options. Assuming that your ftServer is not already configured with its maximum memory and storage, both memory and storage can be upgraded in the future. Memory upgrades are handled by installing additional DIMM chips and require a maintenance window for server downtime. Storage upgrades are handled by installing additional mirrored pairs of disk drives and can be executed while your ftServer is still operating, with no planned downtime or outage required.

Does Stratus offer installation services with ftServer? What is its scope?

Yes, Stratus offers a Jumpstart Installation offering, which can be delivered by Stratus or a certified partner. A trained Stratus or partner Field Engineer will work with you on all aspects of your ftServer installation and configuration. This includes unboxing the server, inspecting for damage incurred during shipping, physically racking the server, cabling the server (power and network), powering up the server, loading the server’s operating system, installing the Stratus Automated Uptime Layer (AUL), configuring the server’s redundant storage and networking, configuring remote monitoring via the Stratus ASN, configuring local monitoring (via OPC UA, SNMP, e-mail alerts, etc.), verifying full duplex operation of the server, assisting with the creation and configuration of up to 4 virtual machines, and providing operating details and administration training to the customer’s team (NOTE: Specific services may vary depending on your region).

Who typically operates, administers, monitors, supports, and services ftServer servers that have been deployed in production?

ftServer is typically managed by inhouse IT and operations staff, third party service providers, or Stratus itself. Due to its simplicity, ease of use, and adherence to industry standards, ftServer is easily administered, monitored, supported, and serviced by either IT or OT personnel. IT teams will feel comfortable with ftServer due to its standard hardware components (e.g., Intel processors, Samsung memory, and Seagate disk drives), it’s standard “shrink-wrapped” operating systems (e.g., VMware vSphere, Windows Server, or RHEL), and it’s IT-friendly monitoring capabilities (e.g., SNMP, e-mail alerts, diagnostics GUI, etc.). OT personnel typically feel very comfortable with ftServer because of its simplicity (two identical halves, or CRUs, that are integrated as a single system and operated like a typical standalone server), it’s OT-friendly monitoring methods (like OPC UA for integration of server health status into the SCADA system and HMI), and most importantly, its highly automated continuous availability and fault-tolerance that keeps VMs and applications up and running with no failover time and no data loss if an issue were to occur.

Does ftServer support redundant networking?

Yes. The ftServer system is based on a dual, redundant architecture, and networking is no exception. Regardless of operating system / hypervisor, ftServer is configured such that multiple network adapters from the top and bottom halves of the server, or CRUs, are teamed together for redundancy. This configuration allows for full network redundancy, such that network communications will continue if the event of failure of a network adapter, a cable, or switch.

Does ftServer support redundant power supplies?

Yes. Each half of an ftServer, or CRU, includes its own dedicated power supply. Separate, independent power supply circuits (with UPS backup) for each CRU are recommended. This power circuit and power supply redundancy ensure continued operation of the server in the event of a power supply failure, or even if a power supply circuit were to trip, or be taken down for maintenance.

What changes do I need to make to my software applications to support running them on ftServer in fault tolerant mode?

None. If your software application is compatible with ftServer’s supported operating systems / hypervisors and guest operating systems, then it will be protected on ftServer with no additional modifications required. By simply running on a fault tolerant ftServer host, it too will become fully fault-tolerant with no other scripting, modifications, or customizations required.

What peripheral cards / devices are supported on ftServer?

Stratus supports certain third party PCIe peripherals for ftServer, and they can be purchased from Stratus. These include Network Interface Cards (NIC – 10 Gbps and 1 Gbps, fiber and copper), and Host Bus Adapter (HBA) cards for interfacing ftServer to external storage arrays. Because peripheral cards require thorough testing / validation and hardened software drivers (to handle transient errors and anomalies with no downtime in a fault-tolerant architecture) any peripheral for use with ftServer must be validated by and purchased through Stratus. Additionally, Stratus offers an “ftReady” program where customers and partners can request that specific peripherals be investigated and qualified for use with ftServer.

What is the recommended architecture for client connections to ftServer?

ftServer supports both thick clients (i.e. physical client workstations with locally-installed applications that request data from ftServer over a network) and thin clients (i.e. terminal devices with no OS or minimal OS that remotely display client applications that are actually running on the ftServer host).

What is the recommended interface type (i.e. hardwired, serial, USB, Ethernet, etc.) for connecting field devices to ftServer?

Ethernet interfaces should be used whenever possible, since multiple types of network adapters (10 Gbps and 1 Gbps, copper and fiber) are available for ftServer, and since the ftServer architecture provides for full redundancy between multiple networks with no downtime or data loss. Other interface types such as USB, serial, hardwired, etc., should be avoided since those interfaces are typically simplex in nature and cannot be integrated to take advantage of ftServer’s redundant fault-tolerant architecture.

Where can I get additional information about Stratus ftServer?

You can get more information about Stratus ftServer from the ftServer product page on Stratus’s website,, or by contacting your local partner or sales representative.