System Health Services

For the most important system resources, the IBM i operating system automatically tracks the highest consumption and consumers.

The IBM i operating system is comprised of many products and components. As an integrated operating system, not only do the products and components frequently rely upon each other, but common building blocks and resources are used. Some of the resources are deemed to be critical because their proper use and consumption is directly related to achieving continued, normal operational behavior. The repository for this tracking lies within DB2 for i.

A table, a view, and global variables combine to provide information about limits on your system. Information about the important limits is logged in a DB2 for i supplied table named QSYS2/SYSLIMTBL. The QSYS2/SYSLIMITS view uses SYSLIMTBL and other DB2 resources to provide extended and formatted detail about these limits. You should generally work with the view rather than the underlying table. You can use DB2 for i provided global variables to control the number of rows kept for each type of limit in SYSLIMTBL.

The limits that are tracked are:
  • ASP limits
    • Maximum number of spool files
  • Database limits
    • Maximum number of all rows in a partition
    • Maximum number of valid rows in a partition
    • Maximum number of deleted rows in a partition
    • Maximum size of a table
    • Maximum number of overflow rows in a partition
    • Maximum number of variable-length segments
    • Maximum number of indexes over a partition
    • Maximum size of a *MAX4GB index
    • Maximum size of a *MAX1TB index
    • Maximum size of an encoded vector index
    • Maximum size of an extended dynamic package
  • File system limits
    • Maximum number of object description entries in a library
    • Number of objects linked in a directory
    • Maximum number of directories linked in a directory
    • Maximum number of file system objects in *SYSBAS ASPs
    • Maximum number of file system objects in an independent ASP
    • Maximum number of document library objects in a folder
    • Number of document library objects in the system ASP
    • Maximum number of document library objects in a user ASP
    • Maximum number of bytes in a stream file
    • Maximum number of bytes in a document
  • Job limits
    • Maximum number of rows locked in a unit of work
    • Maximum number of row change operations in a unit of work
  • Journal limits
    • Maximum size of a journal receiver
    • Maximum number of objects that can be associated with a *MAX10M journal
    • Maximum number of objects that can be associated with a *MAX250K journal
    • Maximum sequence number of a *MAXOPT3 journal
    • Maximum sequence number of a *MAXOPT1 or *MAXOPT2 journal
  • Object limits
    • Maximum number of members in a source physical file
  • System limits
    • Maximum number of jobs