What Is Your Prime Availability Plan for Your SFTP Server?
As organizations and their trading partners become more and more integrated, it’s critical that file transfers perform without delays or disruptions. For instance, a document containing a batch of transactions could traditionally be delivered within a window of several hours without causing any issues. But today, in the effort to make business processes as efficient as possible, that same document must now be delivered within seconds.
Because of this need for instant communication and delivery, organizations are taking a closer look at how they can achieve the best high availability plan for their systems and minimize any potential disruptions to their file transfers.
Comparing High Availability Strategies
Many of the secure file transfers from your trading partners are probably going through an SFTP server in your organization’s network. If that SFTP server went down due to a CPU or drive failure, you would need to fail over to a redundant backup system to continue servicing your trading partners, thus maintaining high availability.
There are two common approaches to high availability : Active-Passive and Active-Active.
1. Active-Passive High Availability
With an Active-Passive approach, only one SFTP server will be active at a time to service your trading partners. A backup copy of the SFTP server would exist on your network as a “passive” system, meaning that it’s installed and configured but isn’t actively running.
To prepare for a potential failure of the active SFTP server, it’s important that you frequently replicate all settings and configuration files from the active SFTP server to the passive system. If the active SFTP server fails, you can then launch the passive SFTP server and configure it to point to this new system.
In an Active-Passive configuration, the downtime for your trading partners (when a failure occurs) can run anywhere between a few seconds to a few hours depending on how the passive system is started.
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The least efficient and often slowest implementation of an Active-Passive approach is to rely on human intervention to detect a failure and manually start the passive system. This implementation could take several hours depending on a few factors:
- When the outage was reported
- How long the process to start the passive system takes
- The complexities of configuring the network to route traffic to the new system.
A much better approach would be to have a third-party system monitoring tool that immediately detects when the SFTP server fails and automatically starts the passive system. The result will be a much shorter disruption for trading partners, usually just a few seconds.
2. Active-Active High Availability (Clustering)
The next level is to use an Active-Active approach, which can also be referred to as “clustering.”
With Active-Active high availability, two or more installations of the SFTP server can run concurrently, sharing the same set of configurations and trading partner accounts. The SFTP servers in the cluster are in constant communication with each other; if one of the SFTP servers fail, the remaining systems in the cluster continue to service the trading partners. This configuration provides the best high availability since it isn’t dependent on human interaction or third-party tools to start up other systems.
Another advantage of an active-active configuration is that you can load balance the traffic over multiple systems, which is important when you need to service a large number of trading partners. Typically, this load balancer resides in your DMZ and acts as your trading partners’ initial point of contact.
The Bottom Line for Your SFTP Server
Both Active-Passive and Active-Active provide high availability for your SFTP server environment if configured properly. However, Active-Active provides the best up-time because it keeps multiple SFTP servers running concurrently in a cluster, along with the added benefit of load-balancing.
How critical up-time is to your bottom line will be the best guide to determining which high availability approach fits your needs.