Miscellaneous limits

There are some other IBM® i system limits, such as the number of basic disk pools, the size of a user space, and the size of a message queue.

Table 1. Miscellaneous limits

Miscellaneous limits	Value
Maximum system and I/O hardware configurations and capacities	See Power Systems™ technical guide in the information center.
Maximum number of disk arms that are contained in all of the basic auxiliary storage pools (ASPs 1 - 32), per partition	2 047
Maximum number of disk arms that are contained in all of the independent auxiliary storage pools (iASPs 33 - 255) in all nodes in a cluster	2 047
Minimum number of disk arms required for acceptable performance.	See Performance Papers and Articles in the Resource Library on the Performance Management Web site.
Maximum number of connections to a disk unit in an Enterprise Storage Server®	8
Maximum combined number of disk arms and redundant connections to disk units1	Approximately 2800
Maximum number of basic user ASPs	31
Maximum number of independent ASPs	223
Maximum number of logical partitions	See Logical partitions in the information center.
Maximum database size for Domino®	64 GB
Maximum size of a user space2	16 773 120 bytes
Maximum size of a user index3	1 TB
Maximum size of a data queue or a user queue4	2 GB
Maximum size of a message queue5	16 MB (approximately 75 000 messages)
Maximum number of new messages of any one message type on a message queue	Limited only by size of message queue
Maximum number of program messages that can be created in a job 6	4 294 967 293
Maximum number of records for each version of the history log	10 000 000
Maximum number of unique Volume IDs displayed/printed in Product Activity Log's Removable Media Lifetime Statistics for each Media Option	5000
Maximum number of input fields that can be specified for a display file	256
Maximum total size of concurrently used teraspace address ranges per job	Approximately 64 TB
Range of user-defined double-byte characters that can be defined and maintained using the character generator utility (CGU) for Japanese	Hexadecimal 6941 through 7FFE
Maximum memory per partition	8 TB
Minimum memory per partition	256 MB
Maximum number of processors per partition	32 processor cores, assuming the processor is running with maximum of SMT4. Can be expanded to 64 processor cores with IBM Lab Services arrangement. This assume processor is running with maximum of SMT4.
Maximum partition ID	1000
Notes: The maximum number of disk arms per partition is limited to 2700. Listed size is the maximum when the machine is allowed to choose the alignment. Absolute maximum size of a user space is 16 776 704 bytes. To create a 1-TB capable user index when using the QUSCRTUI API, specify a value of 1 for the index size option. Otherwise, the size limit will be 4 GB. The maximum size of a data queue that can be created through the data queue host server is 16 megabytes. Message queue QSYSOPR is shipped with a message queue full action of *WRAP. When the message queue is full, the oldest informational and answered messages are removed from the message queue to allow space for new messages to be added. If the removing of the informational and answered messages does not provide enough space, then unanswered inquiry messages are removed until there is space to add the new message. The default reply is sent before an unanswered inquiry message is removed. For more information, see the MSGQFULL parameter on the CHGMSGQ command. If the job has multiple threads, then the limit is the number of messages from all threads combined.