IBM i 7.6 vs Ubuntu: analysis to choose (or combine) wisely
When it comes to IBM Power servers, many decisions seem like a battle between two worlds: the almost legendary robustness of IBM i 7.6 and the freedom of Ubuntu Linux. But what if the best choice is not one or the other, but both? In this article we cut to the chase: we tell you what no one else can explain clearly, without selling you smoke and mirrors, without marrying ourselves to a single approach. Just the technical truth, well told.
IBM i: a closed (but very efficient) fortress
If you’ve worked with IBM i, you know what we’re talking about: stability, performance and a database that won’t crash even if you throw a nasty core dump on it.
IBM i is not just an operating system, but an integrated platform: OS, database (Db2 for i), security, backups, virtualization and native HA (PowerHA, Db2 Mirror) in a single environment optimized for Power10. The integration of these layers avoids intermediate layers or dependencies between external tools.
Technical matters: IBM i runs on a microkernel that manages persistent objects on disk with a native object-oriented, non-file-based model. Its journaling system guarantees consistency even in the face of power outages, and allows remote journaling for DR replication without the need for snapshots.
IBM i 7.6 improves native SQL performance, strengthens security (with integrated multi-factor authentication and more object-level encryption), and enables more modern APIs (REST, OpenAPI, JSON), which allow traditional business logic (RPG, COBOL) to be exposed as microservices. At SIXE we already have an analysis of all the new features of IBM i. If you want to take a look , click here.
Ubuntu in Power: freedom, but with responsibilities
On the other hand, if you are from the Linux team, you already know what Ubuntu brings: DevOps ecosystem, containers, microservices and official Canonical support for Power for years, with optimized images for the ppc64le architecture.
Ubuntu is not plug-and-play like IBM i, but it doesn’t pretend to be either. You can deploy PostgreSQL, MongoDB, Redis, Apache Kafka, Ceph… you name it. And if you mount KVM (already integrated into PowerVM), you can use LXD, OpenStack or orchestrators like MAAS or Juju to manage the environment at scale.
But yes: there is no magic. You’ll have to build the stack yourself: HA with Pacemaker, backups, security with SELinux… And that implies having good Ansible playbooks or well-defined CI/CD pipelines. Nothing is done by yourself.
In HPC and AI, Ubuntu on Power is taking off strong: Power10 (and soon Power11) has brutal bandwidth, and with the upcoming IBM Spyre accelerator on the horizon, you can train models without relying on NVIDIA GPUs.
What about security?
This is where IBM i shines by design: the entire system is security-oriented. Each object has its own authority, with highly granular user profiles and an audit journal that logs everything that happens, without having to install and configure syslog-ng or ELK stack.
Ubuntu, on the other hand, has everything you need: ufw, auditd, encryption with LUKS, application-level protection with AppArmor or SELinux… but you have to integrate it manually and maintain it. A poorly patched Ubuntu environment is an easy target.
On IBM i, security patches are few and far between and controlled; on Ubuntu there are almost daily updates. That’s not a bad thing, but it requires well automated patch management processes.
Costs: beware of what looks cheap
Many people see Ubuntu and say “free!”. But not all that glitters is gold. On Power servers, the hardware is the same, and the operating cost can skyrocket if you don’t automate well or if you need to replicate services that IBM i comes ready to use.
IBM i has a more expensive license, yes. But you can do more with less staff. If your load is critical, stable and doesn’t vary every week, in the medium term TCO can play in your favor.
Modernization: Do I stay with RPG or switch to microservices?
If you have code in RPG, IBM i 7.6 lets you continue to use it… and even modernize it with REST APIs, Node.js or Python (via PASE). VS Code is also getting into the game and is gaining more traction so you can modernize and write code more easily.
Does your team prefer to work in containers, use CI/CD and deploy? Ubuntu. Nothing more to say.
Conclusion: one, the other… or both?
Sometimes it’s not a matter of choosing black or white. In many Power environments, what really works is combining the best of each world. Here are some recommendations:
| Scenario | Recommendation |
|---|---|
| You already have IBM i with RPG | 💡 Follow and modernize from the inside |
| New apps in Power |
🐧 Ubuntu with containers |
| Minimal downtime, no hassle | 🛡️ IBM i + Db2 |
| Total freedom | 🧩 Ubuntu on Power |
| Reduce dependence on IBM in the future | 🔄 Ubuntu with progressive migration |
| Mixed Linux + IBM i equipment |
🐧🛢️Hybrid approach: back IBM i, front Ubuntu |
What if I don’t want to choose?
Good question. In fact, many companies don’t. They use IBM i for critical and stable loads (billing, ERP, etc.), and Ubuntu for everything new: APIs, frontends, microservices, AI.
This hybrid approach gives you the best of both worlds: the reliability of IBM i, with the agility and ecosystem of Ubuntu.
What’s next?
If you are in doubt, in the middle of planning or directly with the licensing Excel open… in SIXE we help you to analyze your environment and design the most realistic way: either maintain, migrate or combine. Fill out the form here and we will contact you.
No smoke. No impossible promises. Only solutions that work (really) and face to face with our engineers.
SIXE
