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Interesting IBM i tip from Integrator team --> Is there a limit on the size of an IBM OS/400 or IBM i5/OS user profile?

Posted: Wed Sep 04, 2019 3:10 pm
by MarkD
Is there a limit on the size of an IBM OS/400 or IBM i5/OS user profile?
If yes, what is this limit?
Is there a limit on the total size of all pointers to objects owned by a user profile?
If yes, what is this limit, and how many objects does that translate into?

This note applies to all releases of OS/400 and i5/OS.
Through V4R3M0, a user profile was limited to 1,048,574 entries.
At V4R4M0, the profile was changed to where it could hold 5,000,000 entries though the OS/400 still supported both sizes of profiles.
At V5R1M0 the system was changed so that as the installation was done, profiles were changed as needed so that all had the format that supported 5,000,000 entries.
At V5R2M0 the profile was again enlarged so it could hold 10,000,000 entries.
As with the prior release, all profiles have the same format and same maximum number of entries.
Additionally, at V5R1M0 for profiles that own, have private authority to, or are the primary group profile for an object on an IASP, an additional 5 (or 10 in V5R2) million entries are available to that specific profile (but those additional entries can be used only for objects on that specific IASP.
They are not available for use by objects in the system ASP.
If a profile has entries for two IASPs, there are 5 or 10 million entries for each such IASP depending upon release level.

The user profile does have a finite size; however, it is composed of two sections.
It is not easy to determine the maximum number of entries.
The main sections consist of an index and a table.
There are several limits associated with a user profile.
The usual reason a user profile fills up is because the table fills up.
The table holds 1,048,574, 5 million or 10 million entries depending on release level.
The maximum size for a user profile is about 48 megabytes (this was true for the 1,048,574 entry table).

At 6.1, the limit on entries for the profile increased from 10 million to 50 million.