IBM i System Limits / Maximum Capacity

Sept 22, 2025

This is something that is overlooked. It is the IBM i System Limits / Maximum Capacity values. The values can be found here. (Change the OS Version as Needed). 

Per IBM "If you exceed system limitations, you might experience an application outage or a system outage. Avoid these types of outages by being aware of the maximum capacities and system limitations in advance."

An example of the # of spooled files allowed on a system / partition:                                                              Maximum number of spooled files in the system and basic user ASP's                                                    Approximately 2,610,000  

 

An SQL like this can quickly provide the answer to how many spooled files are on your system / partition:                                                                                               

 

Select NUMBER_KEYS from QSYS2.SYSPARTITIONINDEXES 

  Where (TABLE_SCHEMA = 'QSPL') and 

              (TABLE_NAME = 'QASPLINFO') and 

              (INDEX_NAME = 'QASPDEVQ') 

 

Here is a breakdown of the query:
Select Number_Keys: This specifies the column to be returned. Number_Keys indicates the number of key columns defined for an index.

From QSYS2.SYSPARTITIONINDEXES: This is the target table for the query. SYSPARTITIONINDEXES is a system catalog view that provides details about all indexes built on tables within the database.

Where (TABLE_SCHEMA = 'QSPL'): This condition filters the results to only include indexes in the QSPL library. On an IBM i system, QSPL is the dedicated library where the system stores its spooled file data.

and (TABLE_NAME = 'QASPLINFO'): This further narrows the search to indexes on the QASPLINFO table. This is a system-maintained table within the QSPL library that holds information about spooled files.

and (INDEX_NAME = 'QASPDEVQ'): This specifies the exact index to be queried, which is QASPDEVQ. This index is used by the system to manage spooled file information. 

In summary, the query is asking the database for the number of key fields that make up the QASPDEVQ index, which is used internally by the IBM i operating system to manage spooled files.