Choose Your Player: Cloud-Based High Availability Options for IBM i Applications
Want to migrate your legacy IBM i to the cloud? Worried your IBM i apps are trapped on-premise? Whichever model enterprise you choose, you have plenty of HA options for IBM i in the cloud.
Join the DZone community and get the full member experience.Join For Free
If an enterprise has been in business longer than five years, it’s safe to say it has legacy business applications such as ERP systems running on IBM i or AIX, along with high availability (HA) software to protect those applications against unexpected outages. The mature HA options for IBM i on-premises can make IT teams reluctant to migrate those legacy business applications to the cloud. As these applications are typically extremely customized, not to mention vital to the business, IT teams must guarantee they are available to users all day, every day.
Luckily, IT has more options here than they may realize. There are solutions that allow IT to have both, running IBM i workloads in the public cloud (while enjoying all the advantages that entails) without losing those strong HA offerings.
Know Your HA
Mature HA solutions for IBM i include PowerHA and MIMIX and are well-loved by many enterprises' IT admins due to their stability, ease of use, and additional useful features like giving users read-only access to backup nodes to produce queries for business analysis. These solutions have existed largely unchanged for many years and IT admins understand how to use them well. They create active-active pairs of applications running in tandem, all from the same database. If the main application fails, the next one takes over to make sure there are no gaps in performance. Not only that, but IT teams can also perform role swaps if needed for system updates and maintenance.
Cloud-native HA options exist, like availability sets, zones, and proximity placement groups in Microsoft Azure, but they are less mature and simply don’t have as robust of features compared to those built for IBM i on-prem. A potential cloud migration puts IT in a bind — if they shift their IBM i applications to the cloud, they will need to move to use cloud-native HA options, reskill their engineers, and potentially lose out on useful features. As many IBM i workloads are at the core of what an organization does (such as point of sales systems for a department store), IT teams must thoughtfully consider all actions that could possibly affect the availability and performance of these systems.
This issue is becoming more and more critical as cloud migrations continue to pick up speed. One survey of Flexera IT professionals found a 16% increase in enterprise cloud spending totaling over $12 million as well as a 9% increase in overall enterprise spending, over $1.2 million in 2021 compared to 2020. An increasing number of enterprises want to consolidate all their data and applications in the cloud to take advantage of solutions such as big data analysis or to better support mobile users. They also might want to migrate traditional applications to the cloud to increase flexibility, get out of the data center, or better control costs.
Keeping PowerHA at Home in the Cloud
IT teams struggling with this choice might have more options than they realize. There are third-party solutions that can reproduce the IBM Power network environment to allow IBM i applications to run in the public cloud unaltered. Using these solutions allows enterprises to maintain their existing mature, stable HA solutions, but also takes advantage of the savings and flexibility of housing those workloads in the cloud.
This model does require some changes to how PowerHA functions and will involve some reduced capabilities. PowerHA on-prem takes advantage of hardware like the Fibre Channel and V7000 database and must use the software equivalents when in the cloud. But the process and overall benefits of PowerHA remain in place.
Many enterprises still want to keep production code running on-premises so they have more control over its performance. In this scenario, migrating HA to the cloud tends to cause problems because the traffic will experience lag time as it moves across the public internet or VPC infrastructure. This depends on the workload and network in question, and sometimes the extra lag time is acceptable. However, generally speaking, the delay involved in switching from on-premises systems to cloud-based is too high for HA.
In this case, running backups and disaster recovery in the cloud and production and HA on-premises is a fantastic model, as it saves on infrastructure costs for disaster recovery workloads and makes them more scalable and resilient (as they can be deployed from separate geographical regions). If a team is wary of the move to the cloud, they may feel safer starting with disaster recovery in the cloud to build confidence and familiarity.
Many IT teams think migrating legacy IBM i workloads to the cloud and refactoring them involves a significant amount of time and considerable risk, plus it will require them to replace the strong HA offerings they know and love with less mature cloud-native versions. On the other side, organizations may worry that their IBM i applications are trapped on-premises because that’s where their preferred HA solution is. But in reality, they have the freedom to choose whatever method works best for their situation. Whichever model enterprise they choose, they have plenty of high availability options for IBM i in the cloud.
Opinions expressed by DZone contributors are their own.