IBM i System Tasks and Their Functions

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Abstract

This is a list of commonly seen IBM i tasks and their functions.

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Task Name	What it does
#w#a#i#t#T#a#s#k	Dedicated processor LPARs will accumulate execution time in the wait-state task when the processor is idle (i.e. all threads idle). Shared processor LPARs should not accumulate execution time in the wait-state task when the processor is idle. When one thread is idle and one non-idle, the wait-state task (running in the idle thread) will accumulate execution time. If utilization was really 100%, there would be no accumulation of execution time in the task.
CFINT##	CFINT## tasks are LIC tasks that essentially do nothing at all. They are just tasks that we charge with the CPU cycles that were used for hardware interrupts. When an I/O completes from disk, tape, or comm I/O, for example, a hardware interrupt is sent to the partition. The hardware interrupt arrives at a processor and there are CPU cycles spent routing the completion back to the job or task that requested the I/O. Those CPU cycles used during that processing aren't charged back to the job or task that requested the I/O but are charged to CFINT## instead.
CFSLT##	CFSLTnn tasks are pseudo tasks reported in Collection Services to aggregate short-lived SLIC tasks. This is an enhancement that was added in 7.1. Rather than cluttering CS with data for many SLIC tasks that live for a very short time (less than 1 second) and are generally unimportant, the data for each of those tasks is aggregated into a single representative task. Usually there is one such representative task per node (so the ## is a hex encoding of the node ID - all of the short lived tasks whose home node is node 0 get aggregated into the CFSLT00 task). Tip: Load/dump tasks frequently qualify as short-lived and so most this is the most likely thing you may be seeing there.
DBIO*	These tasks manage the auxiliary space associated with database files. Auxiliary space is the space associated with variable length character fields. Any job doing operations on files with variable length character fields (for example, a purge job) might cause these jobs to become active.
DBL3Base*	These tasks are used during parallel database operations, such as parallel index builds or EVI scans.
DBPMServer*	These tasks are responsible for pre-bringing auxiliary (AUX) segments. AUX segments are associated with variable length character fields.
DD-FREEAGENT*	The DD- tasks handle DASD hardware driver functions that cannot be performed on a client task. They are used for: - internal DD commands on startup or during resets - dasd microcode downloads - dasd initialization/format processing - dasd error recovery processing - IoStats retrieve measurements requests
IOAM* IOAM-#####-1 IOAM-#####-2	Each storage adapter has 3 IOA manager tasks. For each adapter, the task labeled IOAM--#########-02 is the one that would process query multi adapter status/query array config.
IOCMxxxxxx	xxxxxx is the line description. Task is an inbound task for COM for a physical ethernet card. IOCMETHLIN would be an example for a system whose line description is ETHLIN. xxxxxx will depend on how the administrator names the ethernet line descriptions.
IOSTATSTASK	This task retrieves I/O measurements. It is used by many functions including WRKDSKSTS, WRKSYSSTS, save/restore functions, queries, etc.

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Document Information

More support for:
IBM i

Software version:
All Versions

Operating system(s):
IBM i

Document number:
871316

Modified date:
27 March 2025

UID

ibm10871316

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