Save and restore limits

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Some IBM i system limits relate to save and restore, such as limits for the size of a save file and the size of an object that can be saved.

Table 1. Save and restore limits
Save and restore limits Value
Maximum number of related objects that can be saved or restored in a single save operation1 Approximately 111 000
Maximum number of related internal integrated file system objects that can be saved in a single operation3 Approximately 500 000
Maximum number of unrelated internal database file objects in a library that can be saved in a single operation1,5 Approximately 5.5 million
Maximum number of changed database file members in a library that can be saved by SAVCHGOBJ Approximately 1 million
Maximum number of names in a save or restore command specifying which objects or libraries to include or exclude in the save or restore operation2 300
Maximum number of concurrent save or restore operations Limited only by available machine resources
Maximum size of an object that can be saved Start of changeLimited only by the maximum size of an objectEnd of change
Maximum size of a save file Approximately 2 TB
Maximum size of description data saved for a file or set of related files 1,4 Approximately 4 GB
Maximum number of document library objects (DLO) that can be restored to a single user auxiliary storage pool (ASP) 1 million
Notes:
  1. All database file objects in a library that are related to each other by dependent logical files or shared formats are considered to be related objects. Starting in V5R4, all database files in a library that have referential constraints are considered to be related objects when using the save-while-active function.
    A database file object consists of one or more internal objects. A maximum of approximately 500 000 related internal objects can be saved in a single save operation. One internal object is saved for each database file object, along with the following additional internal objects:
    • If the physical file is not keyed, add 1 internal object per member.
    • If the physical file is keyed, add 2 internal objects per member.
    • If the physical file has unique or referential constraints, add 1 internal object per constraint.
    • If the physical file has triggers, add 1 internal object for the file.
    • If the physical or logical file has column level authorities, add 1 internal object for the file.
    • If you use ACCPTH(*YES) on the save command, add 1 internal object for each logical file in the save request.
  2. Using generic names to specify groups of objects or libraries can help avoid this limit. For the LIB, OMITLIB and OMITOBJ parameters on save commands, you can use the Command User Space (CMDUSRSPC) parameter to raise the limit to 32 767 simple or generic names.
  3. Example of related internal integrated file system objects are objects with multiple hard-coded links or Java programs attached to a stream file.
  4. Description data includes descriptions of files, formats, fields, members, and access paths, as well as general object descriptions. It also includes intermediate source code such as that generated by the SQL precompiler or REXX interpreter. If your save operation exceeds this limit, you may need to save the data without saving logical file access paths, or you may need to omit some files or members and save them in a separate operation.
  5. To activate this limit, create the following data area. CRTDTAARA DTAARA(QSYS/QDBSR256M) TYPE(*CHAR) LEN(1)

    The limit without this data area is approximately 349 000.