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IBM i 7.5: New System Limits and More Hidden Gems

I’ve been reviewing the documentation about IBM i 7.5 and have discovered more hidden gems. Continuing from the post last week, here are more of my favorites:

Historical Data Collection Is on by Default

I submitted an IBM Idea asking that Collection Services enable historical data by default. I am happy to report this feature is now a part of 7.5. I found this gem hidden in the Memo to Users. However, it is limited to new installations of IBM i 7.5. If you are upgrading from a prior release, the existing historical data configuration will not be changed.

Tip: Enable historical data collection on your IBM i partitions.

Maximum Capacities: Number of Entries in a User Profile

Several system limits were increased, one of which was the maximum number of entries in a user profile. I had written about this limit in “When Does a User Profile Becomes a Bottleneck?” This larger limit is a good change, particularly if you have user profiles own a lot of objects in the IFS.

Related to the number of entries in a user profile, the QSYS2.USER_STORAGE service, is now able to return several additional columns of information about the authority-related entries in the user profile. This provides valuable information to help understand why a user profile has a large number of entries.

Asynchronous Bring Default Is Now *YES

Another tidbit hidden in the Memo to Users, the Asynchronous Bring (ASYNCBRING) parameter for IFS saves is now changed to a default of *YES. This parameter was introduced several years ago and *YES generally improves the performance of IFS saves. My “Achieve Faster IFS Save Times with ASYNCBRING” blog post originally described this feature.

No-Charge Features

In his post, “What’s New with Db2 for i 7.5” Kent Milligan wrote that several options of the OS that used to be chargeable are now no-charge features. Db2 Multisystem, Db2 SMP and HA Journal Performance are included for no charge with 7.5. It is great to have these features available, but Db2 SMP and Db2 Multisystem need planning before you use them.

I know of many smaller shops that will benefit from HA Journal Performance (journal caching), but could not justify the additional cost to purchase the product.

IBM has also added additional controls for Db2 SMP. In my experience, Db2 SMP can consume a lot of system resources, in particular, CPU, and additional knobs to better control Db2 SMP resource consumption is a good thing.


Of all the many new services to pick from, QSYS2.MTI_INFO requires special mention. I recently worked with several clients that have huge amounts of temporary storage consumed by Maintained Temporary Indexes (MTIs). MTI_INFO is very useful for evaluating the MTIs and determining if creating permanent indexes is beneficial. I expect to utilize this feature quite a bit in the future.