OS/400 Main System jobs

When you use the command wrkactjob to check the running status of a job, you will often find some system jobs, but it is unclear what these system jobs are used, this article will introduce the usage of some major system jobs.
A text system job is created and controlled by OS/400. It is used to control system resources and process system-level requests. In the command
In the jobs displayed in wrkactjob, system jobs are sorted alphabetically after all user subsystems and jobs.

System jobs are initialized when the system IPL is used. However, as long as the OS/400 system is active
Qwcbtclnup and qdcpobjx will also maintain the same activity. System jobs cannot be started, stopped, or changed by users (except a few system jobs can be changed by using the command chgsysjob, And the only attribute that can be changed by this command is the running priority of these system jobs .)

The following describes detailed information about the system operations:

-- Qalert-Alert Manager alarm Management
This system enables the job to handle alarms, including alarms received from other systems, alarms generated by the local machine, and maintain system control. You can use the command chgsysjob to change the priority of qalert jobs. This job is added to the operating system when OS/400 r220 is used to support alarm information processing.

-- Qcmnarbxx-Communications arbiters
The communication arbitration server handles not only communication devices, but also all types of other devices. Communication, disconnection, device lock, and error recovery are involved. All device-related work is distributed in qcmnarbxx and qsysarb.

System
Qcmnarb determines how many communication arbitration tasks are initiated. If qcmnarb is set to * calc, the system starts two communication arbitration tasks for each processor. If qcmnarb is set
Set to 0, and the job will run in qsysarb. You can use the command chgsysjob to change the job running priority of qcmnarbxx. Added in job qcmnarbxx
Before OS/400 r420, these jobs were run in qsysarb.

-- Qdbsrvxr-database cross-reference database cross reference
The
A job is used to maintain file-level system cross-reference files in qsys. These files store cross-reference information of database files, and these files start with qadb in qsys. Primary
The maintained file is the cross-reference file qadbxref, which contains records of every physical file, logical file, DDM file, and alias file in the database. When a file is created, modify
When changing, deleting, restoring, renaming, or ownership, the job qdbsrvxr is activated. This job is added to the operating system in OS/400 r310.

-- Qdbsrvxr2-database cross-reference database cross reference
The
A job is a system cross-reference file used to maintain two fields. qadbifld in qsys is a cross-reference file for fields, and qadbk1_in qsys is a cross-reference file for key words.
When a file is created, changed, or deleted to run key-word-related work, the job qdbsrvxr2 is activated. Qdbsrvxr2 by PTF iN OS/400
R310 is added to the operating system. You can use the command chgsysjob to change the job running priority of qdbsrvxr2.

-- Qdbsrv01-Database Server
This job can be considered as a database maintenance task distributor. Generally, qdbsrv01 is activated immediately when a database containing database files is recovered. Its functions include:
* Send a signal to the smapp (system-managed access path protection mechanism) to notify the new access path to be restored, and the amapp determines whether the access path needs to be protected.
* Because the access path is not restored, the list of access paths to be re-created for the job preparation. You can run the edtrbdap command to view the list.

Quantity
The number of database server jobs is (1 + 2 * CPU) and (1 + 2 * ASP. The minimum number of started instances is 5. Qdbsrv01 is the main system job used
For other jobs, half of the remaining jobs are used to process high-priority requests, and the other half is used to process low-priority requests. For example, in a 4-way CPU system, there should be 9
Qdbsrvxx job, assigned by qdbsrv01, QDBSRV02-05 for high-priority jobs, QDBSRV06-09 for low-priority jobs.
This job is added to the operating system in OS/400 r210.

-- Qdbsrvxx-Database Server (high priority)
These jobs maintain system log and submission control.

-- Qdbsrvxx-Database Server (low priority)
These jobs are used to maintain the access path of the user's database files. These jobs are usually not active, but they are activated under specific conditions for reconstruction of access paths. You can run the edtrbdap command to browse the reconstructed access paths. The reasons for activation of these jobs include:
* Restore database files that do not save the access path;
* Restore logical files without physical files;
* Cancel the running command rgzpfm;
* The index becomes invalid because it is damaged;
* Accelerate OS/400 installation for cross-reference or other DB2 upgrade operations;
* Verification constraints. Run the edtcpcst command to display the constraints that are waiting for verification.

-- Qdcpobjx-decompress System Object Decompression
These jobs are used to extract the newly installed operating system objects, and their operation requires a certain amount of space. When your system space is low to a certain extent, these jobs will end. Number of System Object decompression jobs = number of CPUs + 1. This job is added to the operating system in OS/400 r210.

-- Qfilesys1-File System
This job is used to support the background operation of file system jobs. It ensures that all changes to files are written to the storage media and performs regular file system cleanup activities. This job is added to the operating system in OS/400 r210.

-- Qjobscd-Job Schedule Job Scheduling
This job controls the job scheduling function, and the system monitors the timer and scheduled jobs of Job Scheduling items.
This job is added to the operating system in OS/400 r220.

-- Qlur-lu 6.2 resynchronization (LU 6.2 Re-Sync)
This job processes two-step submission for re-synchronization. This job is added to the operating system in OS/400 r310 and is part of the Lu 6.2 communication protocol.

-- Qlus-logical unit services logical unit service
This job processes events handled by logical unit devices (communication devices). It is also responsible for locating devices to the correct communication subsystems. Qlus is one of the original system jobs on AS/400.

-- Qpfradj-performance adjustment performance Adjustment
Sex
Allows you to adjust the size and activity level of the system Job Management storage pool. All requests that require changing the storage pool size are processed by this job. In addition, if the system value qpfradj is set to 2 or 3, the job dynamically
To improve the system performance. In OS/400
R430, IPL performance adjustment (the system value qpfradj is set to 1 or 2) is handled by qpfradj, on OS/400
Before r430, the performance of IPL was adjusted by scpf. Qpfradj is added to the operating system on OS/400 r210.

-- Qqqtemp1 and qqqtemp2-database parallelism Database Parallel
This job is used to synchronize databases in multiple DB2 systems. If you query distributed files, this job can speed up processing by executing parallel processing. It is added to the operating system as the DB2 multi-system support function in OS/400 r370.

-- Qsplmaint-system spool maintenance Offline Management
This job is used to maintain the system off-line.

-- Qsysarb-system arbiter system Arbitration
System
System arbitration provides an environment for running the high-priority function. It processes system resources and keeps track of the system status. Qsysarb is the core operating system job. System arbitration is responsible for system-level, which must be handled immediately and
Tasks that can be processed more effectively by a single job. System arbitration is also responsible for processing communication requests, Device Locks, line/controller/device configurations. System arbitration is one of the most primitive operations in OS/400.

-- Qsyscomm1-System Communications System Communication
This job processes system communication and I/O. The job priority of qsyscomm1 can be changed using the command chgsysjob, which is added to the operating system in OS/400 r320.

-- Qwcbtclnup-job table cleanup job table clearing
Qwcbtclnup
Is used to ensure that the job structure can be used in the IPL process. Generally, when IPL ends, the job also ends. However, if many job structures need to be cleared, it can continue to run after IPL ends.
Line. The system job is finished after processing. Qwcbtclnup is added to the system when the job table is removed from scpf iN OS/400 r210.

-- Q400filsvr-Remote File System Communications Remote File System Communication
This job processes the universal programming interface communication of the Remote File System Appn/APPC. Q400filsvr is in OS/400
R360 can be added to the operating system as remote files.

-- Scpf-Start Control Program Function
This job is the central processing task of the operating system IPL. It provides the OS/400 startup environment and the directly needed functions. Scpf starts all other system jobs (except qlus) and brings the system into the available status. Scpf is one of the most primitive jobs in OS/400.