Automation and System Redundancy
Industrial automation requires a high degree of reliability, and this requirement extends to the computing hardware and software needed to run automated systems. High availability has been designed into low-level system components such as embedded controllers for many years.
But today's automated equipment is expected to perform new tasks - such as communicating information to backend databases - as part of an increasingly integrated and intelligent infrastructure. As automated systems are required to do more and systems become more complex, companies have an opportunity to step back and evaluate where they can most effectively and cost-efficiently build redundancy into the computing infrastructure.
Building High Availability
To evaluate redundancy opportunities within a system, it is best to start at a high level with the software. Consider high-level subsystems such as the database and the administrative console and prioritize where to invest in high availability. If a particular subsystem depends on continuous information updates, then the data store should be highly available to that subsystem.
The next step is to determine a strategy for building the required availability levels into the various subsystems. If the database must be highly available and is supported by multiple server nodes, how should demand be distributed across those nodes, especially if one of them fails? Several options are available for configuring nodes to provide high availability, including software and hardware solutions.
Configuring Hardware for Redundancy
In addition to building high availability into systems at the software level, organizations should ensure hardware supporting those systems is not dependent on any single point of failure. Organizations can help prevent failure through hardware redundancy and repairability on the fly. At the server level, redundancy is essential to ensure continuous, reliable computing, and data storage.
Hardware redundancy starts with the selection of server technology. Blade servers, which consist of a chassis that houses multiple servers operating as individual computers, offer built-in failover and redundancy features for maximum system uptime. Organizations with a growing number of servers should consider blade server technology.
A blade system chassis can host multiple server blades plus shared infrastructure components, and redundancy is built into the blade architecture by providing more than one of each component to avoid single points of failure.
Additionally, these components are ideally shared through the midplane, which is passive to help ensure high reliability, the midplane contains no active logic, only connectors and traces.
Redundant hardware components can include:
- Redundant and hot-pluggable chassis cooling fans
- Redundant chassis management modules
- Standard N-1 redundant hot-plug power supplies
- Optional redundant RAM
- Redundant storage with hot-plug hard drives
- Battery backed-up RAID cache
- Redundant network interfaces
- Redundant hot-plug switch modules
Providing Backup for Power, Cooling
Power supply is a critical element that must be protected at multiple levels. Organizations wanting a true high-availability solution should consider purchasing power from two different utility companies. If one utility experiences an outage, the other can continue to provide service. In addition to power source redundancies, organizations commonly deploy multiple uninterruptible power supply units to provide emergency power to the facility if the utility mains fail.
Well-designed blade servers also ensure network connection redundancy, with chassis I/O modules providing external connectivity and multiple internal ports for connecting to the blades. Each blade commonly includes dual Ethernet network interface cards (NICs) or embedded network LAN on Motherboard (LOM) units.
Deciding Where to Invest
Redundancy is essential for avoiding costly stoppages and downtime, especially where automated manufacturing and processing is concerned. But few organizations find it cost-effective to build the same level of redundancy and availability into every part of the operation. As infrastructure grows increasingly integrated and intelligent, companies have an opportunity to change the architecture of their systems so availability does not depend on every single processor and capacitor, but is also built into databases, interfaces, and applications.
The key is to be selective about where to invest in redundancy. By starting with the overall system, assessing which subsystems are required to be highly available, and considering the software environment as well as the hardware domain, MechoTech can help organizations achieve the high availability they need while driving down costs. For more information, contact MechoTech, LLC at (949) 215-7270 or visit www.MechoTech.com