Page 44 - Security Today, March 2017

These effects may be magnified even further in buildings without on-site IT staff available to move quickly to deal with server failure in an emergency. So if the 24/7/365 availability of such physical security systems has become absolutely critical in an IIoT world, what are the best approaches to maintaining server availability? I’ve outlined the three most common below:
Data backups and restores. Perhaps the most basic approach to server availability is to have basic backup, data-replication and failover procedures in place. In particular, this will help speed the restoration of an application and help preserve data following a server failure.
If backups are only occurring daily, however, you may only be guaranteeing 99 percent availability and significant amounts of data can be lost. Considering this equates to an average of 87.5 hours of downtime per year, or more than 90 minutes of unplanned downtime per week, most businesses cannot tolerate losing critical building se- curity and life-safety applications for that long.
High availability (HA). HA includes both hardware- and software- based approaches to reducing downtime. HA clusters combine two or more servers running with an identical configuration and use soft- ware to keep application data synchronized on all servers. If there is a single failure, another server takes over with little to no disruption. These can be complex to deploy and manage, however, and require that you license software on all cluster servers, which is an added cost.
On the other hand, HA software is designed to detect evolving problems and proactively prevent downtime. Using predictive analyt- ics to identify, report and handle faults before an outage occurs, this software can run on low-cost commodity hardware and still offer the proactive advantage over HA clusters. HA provides from 99.95 per- cent to 99.99 percent (or “four nines”) uptime, equating, on average, from 52 minutes to 4.5 hours of downtime per year—significantly better than basic backup.
Continuous availability (CA). Finally, through the use of sophis- ticated software or specialized servers, “always on” solutions aim to reduce downtime to its lowest practical level. Using software, each application lives on two virtual machines, mirroring all data in real- time. If a single machine fails, applications can still run on the oth- er with no interruption or data loss. If a single component fails, a healthy component from the second system automatically takes over.
CA software can also facilitate disaster recovery with multi-site capabilities. If a server is destroyed by fire or sprinklers, for instance, the machine at the other location will take over seamlessly. This soft- ware-based approach prevents data loss, is simple to configure and manage, requires no special IT skills and delivers upwards of 99.999 percent availability (about one minute of downtime a year)—all on standard hardware.CA server systems rely on specialized servers pur- pose-built to prevent failures from happening. They integrate hard- ware, software and services for simplified management and feature both redundant components and error-detection software running in a virtualized environment.
Vulnerability of an Operation
Of the three availability approaches listed above, the one that is the best fit for your building security applications will depend on a range of factors. First, it’s important to determine the state of your current security automation infrastructure. While your system architecture may be billed as “high availability,” this term is often used to describe a wide range of failover strategies—some more fault-tolerant than others.
In the event of a server failure, will there be a lapse in security? Will critical data be lost? Is failover automatic or does it require manual intervention? Assessing the potential vulnerabilities of your infrastructure can help you avoid a false sense of security that could come back to haunt you. This insight will help define your needs and guide you toward the most appropriate availability strategies
for your security environment.
How Much Availability Do You Need?
Deploying the highest level of CA for all of your security applica- tions across the enterprise would obviously be ideal, but the cost may not make sense in every instance and not all security applications require the highest level of uptime. Some applications, for instance, may work best in a multi-tiered approach. This could involve a cen- trally-located “master server” controlling a network of site servers that regularly cache data back to the master.
Here, you might configure the master server as CA, but decide that HA is adequate for the site servers given their workloads. The criticality of each server’s function within the security automation ar- chitecture will ultimately inform this decision, and carefully assessing your requirements for each will help balance real-world needs with the realities of your budget.
The Airport’s Solution
To wrap up the airport example from above, they determined the se- curity of their implementation was critical enough and had enough business impact that they would need a full fault-tolerant solution that ensured continuous availability. Their CA solution needed to be deployed across multiple physical servers geographically separated by about a mile. After installing CA software, the airport experienced zero unplanned downtime, was able to scale their systems after open- ing another terminal for 55 million more passengers annually, and even maintained seamless operations after a major water leak flooded one of the airport’s datacenters. At the end of the day, performing a comprehensive assessment of availability needs ended up saving the airport from a variety of complicated security issues down the line.
Putting Your Strategy in Place
Whether you are expanding or upgrading existing building security infrastructure to support an IIoT environment, or building a new in- frastructure from the ground up, consider these tips.
• Think about server availability as a core requirement—plan-
ning early can help you avoid problems that crop up when try- ing to “tack on” an availability solution later in the architec- ture and deployment cycle.
• Carefully assess the availability requirements of all your secu- rity applications and determine how much downtime you can afford for each. This will help guide you to the appropriate availability solution needed for each application.
• Be wary of classic, non-virtualized cluster systems that require many interactions between the security application and clus- ter software, increasing complexity and making management more challenging. Solutions that minimize intrusion into the application space are more flexible and easier to manage.
• Work with building automation vendors that are familiar with availability and have the knowledge to guide you to solutions that are suitable for your unique deployment.
Server availability needs to be the cornerstone of any perimeter
security strategy and will alleviate a variety of concerns for opera- tors, both in the day-to-day management of security operations and when emergency situations arise that affect security. Ultimately, having a clear idea of what your perimeter se-
curity system needs to keep critical applications available is the most important step to main- taining security in an increasingly-connected, “always on” world.
Robert Otto is the director of product manage- ment at Stratus Technologies.
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