IBM Streamlines Data Migration With New Partition Mirror Tech

July 28, 2025 Alex Woodie

There is a brand new technology available for migrating data from one IBM i partition to another as part of IBM’s new Migrate While Active tool. It’s called partition mirror, and it gives IBM i shops a potentially less disruptive method for moving data across distances both long and short.

IBM first unveiled its new Migrate While Active product in October 2024 as part of its announcement introducing subscriptions for the PowerHA high availability and Db2 Mirror continuous availability products. The co-mingling of the announcements made some sense when you consider that the original Migrate While Active product utilized a Db2 Mirror protocol to move data from on-premises systems to IBM i instances running in PowerVS, IBM’s cloud offering for Power Systems.

However, things have changed for Migrate While Active in just the course of a few months. For starters, IBM isn’t limiting Migrate While Active to being used to load data into PowerVS. The company is promoting the product as a tool for customers to move IBM i data wherever it might be, including from on-prem to the cloud, from the cloud to on-prem, between two clouds, or from one on-prem location to another.

Partition mirror is a new data migration technology available as part of Migrate While Active. (Image courtesy IBM)

Here’s another difference: IBM won’t be limiting itself to just that original Db2 Mirror protocol with Migrate While Active. In fact, IBM will be using an array of different technologies depending on what customers want to do, according to Scott Forstie, the business architect in charge of the Db2 database at IBM.

“We have these things called migration patterns, and the pattern dictates how are you going to get from A to B,” Forstie told IT Jungle at the recent POWERUp 2025 conference. “And there’s different technologies you can use, and in the future there’ll be even more technologies.”

Well, it didn’t take long for IBM to announce one of those new technologies. As part of its big Power11 launch on July 8, IBM revealed that it’s adding partition mirror to the Migrate While Active product lineup. (Migrate While Active apparently will never get its own announcement day.)

According to IBM, partition mirroring uses a host-based, asynchronous storage replication technology that lives beneath the technology-independent machine interface (TIMI) underneath the IBM i operating system to copy data residing in the system base ASP (SYSBAS) from the source to the destination.

This approach brings several benefits compared to the initial replication method on Migrate While Active. For starters, partition mirroring does not require an initial outage on the source system “because the creation of install media or a full system save is not necessary,” IBM says. And because partition mirroring it sits below TIMI, “there are no locking considerations or conflicts with on-going production workloads.”

Administrators can monitor and control the partition mirroring activity from Db2 Mirror’s GUI (purchase of the full Db2 Mirror is not required). Once all of the data has been migrated, partition mirroring will continue to replicate any changes that are made to the data.

Partition mirror supports a test mode that allows users to check the integrity of migrated data. (Image courtesy IBM)

IBM also supports a test mode with partition mirroring that allows users to check whether everything is working on the target system. During testing, replication is suspended, and any changes that a user makes to the data during the course of testing is tracked. Once the user is happy with the replication, the changes made to the target node are rolled back and replication is restarted to bring the target node back in synch with changes made on the production system. At that point, a final cutover is performed to complete the migration.

There are some caveats to the new technology that customers should be aware of. The technology does not support encrypted data, so if customers have any encrypted data in their ASPs, it will not be replicated. The new replication method also does not support independent ASPs (iASPs). It also only supports IBM i version 7.4 with Hardware Technology level 12 at this point, although IBM did issue a statement of direction indicating it will soon support IBM i 7.5 and IBM i 7.6.

The new partition mirroring will be a gamechanger for customers migrating into PowerVS, according to Doris Conti, IBM’s vice president of Power Systems product management.

“We are so confident on the progress we have made with migration and onboarding that we are now offering a five-day onboarding guarantee,” Conti said during the Power11 launch even on July 8. “If you want to adopt hybrid cloud for strengthening your business reliance, if you want to accelerate your application modernization, or you want to place workload based on your business needs on PowerVS, we can get you going on PowerVS in five days or less.”

Don’t be surprised if IBM brings even more new tech to Migrate While Active.

“Our team is having a big year focused on Migrate While Active, so I expect it to be an exciting year with deliveries throughout and maybe even into the following year,” Forstie said. “Why? Because we’ve got so much interest. And there’s different patterns of what people want. So we need to enhance that product to meet the needs of the clients. And I’m expecting it to be an exciting year.”

You can learn more about partition mirroring here.

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