Blog | Roadblock? Don’t let AS400 disrupt your journey to the Cloud

July 6, 2021 Claranet Limited

Roadblock? Don’t let AS400 disrupt your journey to the Cloud

Jay Fearn
Principal Solutions Architect at Claranet

Your younger applications are only too happy to pack their bags and move home. But your older, business-critical systems may need a lot more care and attention. Jay Fearn, Principal Solutions Architect at Claranet, maps out the issues. 


As many businesses look to move to the Cloud and gain the benefits of greater flexibility, reliability, security, compliance, and scalability, it is increasingly apparent that some are finding they are being held back by their old legacy systems.  

A typical case in point is the AS400 operating system, now also known as the IBM iSeries. Still one of the most robust and reliable system architectures used by many organisations, AS400 servers are typically the central system within an organisation, being the single source of truth for organisational data, and tend to run business-critical workloads.  

If they were to break or stop working, it would cause great harm to the business, be it financial or a loss of reputation. Therefore, some businesses are reluctant to start the journey to the Cloud, as the risk is too high if these systems were to fail.  

"AS400 migrations to the Cloud require a very specific set of skills and experience."

Maintaining these systems is a necessity to meet business needs and ensure business continuity with the existing AS400 platform. But managing legacy operating systems is also becoming increasingly difficult to support due to the lack of qualified staff.  

So, it’s no surprise that as the rest of the data centre is migrated to the Cloud, customers do not want to leave their AS400’s behind. Whereas migrating legacy operating systems can be complex and present a risk to business-critical infrastructure, the high cost of maintaining them in traditional hosting environments is not an option anymore.  

That said, AS400 migrations to the Cloud do require a very specific set of skills and experience.  

There are many approaches to performing a migration of legacy systems, but they should all start with an in-depth discovery stage to document the current landscape (scope). Only after a complete discovery can a more detailed plan be drawn up. Significantly, there is never an ideal one-size-fits-all approach for AS400 migrations, as it varies from business to business depending upon the desired goal.  

This plan will consider any of your specific business requirements, like downtime windows, personnel availability, and times to avoid such as end of month/year processing. The important parts of any plan when moving any legacy system is the surrounding infrastructure. For example: what talks to the server/partition; at what frequency; and the effects of any changes to the end-users when the latency changes.  

The actual moving of the systems is relatively easy. It is just a logistical exercise and could be based on one or more of the following: 

  1. Physical Lift and Shift where existing interfaces or functionality are kept unchanged.  
  2. Using Tapes or Virtual Tapes to restore to a new or reconditioned box.  
  3. Replicate and failover to an existing DR, new or reconditioned box.  
  4. Failover to a Cloud Provider who has an IBM iCloud Service (IBM, Claranet) to future-proof the architecture.  

All or a mix of the above could form the foundation of a migration strategy, depending on the current setup and specific business requirements.  

As I have already mentioned, finding qualified personnel for managing AS400 systems has become a real challenge, which is why many companies are reaching out to technology partners to manage the migration of old IBM systems into their cloud infrastructure. It’s an option worth considering because this can lead to migrations in a matter of weeks with no data loss, no unexpected glitches, and no impact on their day-to-day tasks.  

In short, don’t let legacy systems hold back your journey to the Cloud. There are solutions to help you navigate the most complex migration paths and improve for the future. 

Learn more about migrating legacy systems to the Cloud. Watch the video >

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