10 Reasons for the Success of Db2 for z/OS

Db2 for z/OS has proven successful for decades not because of any single feature, but because it consistently delivers on the things that matter most for mission-critical enterprise computing. The biggest reasons fall into a few clear and convincing categories.

1. Unmatched Reliability and Availability

At the top of the list is availability. Db2 for z/OS is engineered to run continuously, often measured in years of uptime rather than days or months.

Key contributors include:

• Robust logging and recovery mechanisms

• Online maintenance (schema changes, reorgs, index builds)

• Data sharing across multiple Db2 members in a Parallel Sysplex

• Automatic restart and failure isolation

For businesses where downtime directly translates to lost revenue, regulatory exposure, or reputational damage, this reliability is non-negotiable... and Db2 has consistently delivered it.

2. Exceptional Performance at Massive Scale

Performance is a hallmark of Db2 systems and applications. Db2 for z/OS excels at high-volume, high-concurrency transaction processing. It routinely handles:

• Tens of thousands of transactions per second

• Millions of SQL statements per hour

• Thousands of concurrent users

This performance advantage is not accidental. Db2 is tightly integrated with IBM Z hardware features such as:

• Specialty processors (zIIP, and previously zAAP which has been rolled into the zIIP funtionality)

• Large memory footprints with sophisticated buffer management

• Hardware-assisted compression and encryption

The result is predictable, repeatable performance even under extreme workloads.

3. Deep Integration with the z/OS Platform

Unlike databases that are merely hosted on an operating system, Db2 for z/OS is co-engineered with z/OS and IBM Z hardware.

This integration enables:

• Advanced workload management (WLM)

• Superior I/O handling

• System-level security and auditing

• Fine-grained resource governance

Because the database, OS, and hardware evolve together, Db2 can exploit platform innovations faster and more effectively than loosely coupled systems.

4. Rock-Solid Data Integrity and Consistency

Db2 for z/OS has earned a reputation as the system of record because it protects data integrity above all else.

This includes:

• Full transactional integrity (ACID compliance)

• Enforced referential integrity and constraints

• Proven locking and concurrency control

• Bulletproof recovery from failures

Enterprises trust Db2 with their most valuable data including financial records, customer accounts, order entry details, healthcare information, flight tracking and more. When correctness is not optional, Db2 for z/OS is the answer!

5. Security Built In, Not Bolted On

Security has always been foundational to Db2 for z/OS, not an afterthought.

Its strengths include:

• Tight integration with RACF and z/OS security services

• Granular authorization at table, column, and row levels

• Native encryption for data at rest and in flight

• Comprehensive auditing and compliance capabilities

For highly regulated industries, Db2 simplifies compliance while reducing risk exposure.

6. Backward Compatibility and Investment Protection

Few platforms can match Db2’s commitment to backward compatibility. Applications written decades ago often continue to run unchanged today.

This provides:

• Long-term investment protection

• Lower modernization risk

• Predictable upgrade paths

Organizations can adopt new Db2 features incrementally without rewriting core applications which is a critical factor in long-term platform success.

7. Continuous Evolution Without Disruption

Db2 for z/OS has evolved continuously while maintaining stability. Over the years it has added:

• Support for new SQL standards

• XML and JSON capabilities

• Temporal tables

• Advanced analytics functions

• RESTful access and modern connectivity

Importantly, these enhancements arrived without forcing disruptive migrations, a balance few platforms achieve.

8. Alignment with Business-Critical Workloads

Db2 for z/OS was designed from the start to support workloads that:

• Cannot fail

• Cannot lose data

• Cannot tolerate unpredictable performance

Industries such as banking, insurance, government, retail, and transportation still depend on these characteristics. As long as these workloads exist, Db2’s value remains clear.

9. A Mature Ecosystem and Skilled Community

Db2 benefits from:

• Decades of operational best practices

• A rich ecosystem of tools (monitoring, tuning, recovery, automation)

• A global community of experienced professionals

This maturity reduces risk and accelerates problem resolution which is another quiet, but powerful, contributor to its success.

10. Trust Earned Over Time

Perhaps the most important reason for Db2 for z/OS’s success is trust. Enterprises have seen it perform reliably through:

• Hardware generations

• Economic cycles

• Technology shifts

• Organizational change

That trust is hard to win... and even harder to replace.

In Summary

Db2 for z/OS has endured not because it resists change, but because it embraces change without compromising stability. Its success rests on a rare combination of reliability, performance, security, and evolution. And these qualities remain just as relevant today as when the platform was first introduced.

A Forced Tour of Duty

Mainframe developers are well aware of the security, scalability, and reliability of mainframe computer systems and applications. Unfortunately, though, the bulk of new programmers and IT personnel are not mainframe literate. This should change. But maybe not for the reasons you are thinking.

Yes, I am a mainframe bigot. I readily admit that. In my humble opinion there is no finer platform for mission critical software development than the good ol’ mainframe. And that is why every new programmer should have to work a tour of duty on mainframe systems and applications after graduating from college.

Why would I recommend such a thing? Well, it is because of the robust system management processes and procedures which are in place and working extremely well within every mainframe shop in the world. This is simply not the case for Windows, Unix, and other platforms. By working on mainframe systems newbies will learn the correct IT discipline for managing mission critical software.

What do I mean by that? How about a couple of examples: It should not be an acceptable practice to just insert a CD and indiscriminately install software onto a production machine. Mainframe systems have well-documented and enforced change management procedures that need to be followed before any software is installed into a production environment.

Nor should it be acceptable to just flip the switch and reboot the server. Mainframe systems have safeguards against such practices. And mainframes rarely, if ever, need to be restarted because the system is hung or because of a software glitch. Or put in words PC dudes can understand: there is no mainframe “blue screen of death.” Indeed, months, sometimes years, can go by without having to power down and re-IPL the mainframe.

And don’t even think about trying to get around security protocols. In mainframe shops there is an entire group of people in the operations department responsible for protecting and securing mainframe systems, applications, and data. Security should not be the afterthought that it is in the Windows world.

Ever wonder why there are no mainframe viruses? A properly secured operating system and environment make such a beast extremely unlikely. And with much of the world’s most important and sensitive data residing on mainframes, don’t you think the hackers out there would just love to crack into those mainframes more frequently?

Project planning, configuration management, capacity planning, job scheduling and automation, storage management, database administration, operations management, and so on – all are managed and required in every mainframe site I’ve ever been involved with. When no mainframe is involved many of these things are afterthoughts, if they’re even thought of at all.

Growing up in a PC world is a big part of the problem. Although there may be many things to snark about with regard to personal computers, one of the biggest is that they were never designed to be used the way that mainframes are used. Yet we call a sufficiently “pumped-up” PC a server – and then try to treat it like we treat mainframes. Oh, we may turn it on its side and tape a piece of paper on it bearing a phrase like “Do Not Shut Off – This is the Production Server”… but that is a far cry from the glass house that we’ve built to nourish and feed the mainframe environment.

Now to be fair, strides are being made to improve the infrastructure and best practices for managing distributed systems. Some organizations have built an infrastructure around their distributed applications that rivals the mainframe glass house. But this is more the exception than the rule. With time, of course, the policies, practices, and procedures for managing distributed systems will improve to mainframe levels.

But the bottom line is that today’s distributed systems – that is, Linux, Unix, and Windows-based systems – typically do not deliver the stability, availability, security, or performance of mainframe systems. As such, a forced tour of duty supporting or developing applications for a mainframe would do every IT professional a whole world of good.