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In this document, the guide is presented only for operating system related items to be set before Altibase is installed, and refer to the separate document "Altibase Configuration File Guide" for setting Altibase properties for setting Altibase itself.. 

Kernel Parameters

When operating Altibase on the AIX OS, it describes the types of kernel parameters that need to be changed, and why the settings need to be changed, and introduces how to change the kernel parameters.

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However, starting from AIX 6.1, the default value of Posix AIO is amiable'Available', there is no need to set it separately.

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For reference, there are no relevant parameters under AIX 5.2 ML03, and there is no change starting from AIX 6.1 , so it is not necessary to refer to it depending on the operation system version.

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After running smit, move the items in the order of "Devices", "Asynchronous I/O" to change the defined 'Defined' state of "Configured Defined Asynchronous I/O" to 'Available'.

However, if only this process is performed, the following process must be performed as the previous Posix AIO setting may be reset when the system is restarted.

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Environment VariableDescription
AIXTHREAD_MNRATIOThe number of k kernel threads for processing n user threads
AIXTHREAD_SCOPESets the thread model to 1:1
AIXTHREAD_MUTEX_DEBUGThe mutex and condition variables being used by the pthread library, The overhead of the read/write lock used by the debugger. Sets to remove.
AIXTHREAD_RWLOCK_DEBUGThe mutex and condition variables being used by the pthread library, The overhead of the read/write lock used by the debugger. Sets to remove.
AIXTHREAD_COND_DEBUGThe mutex and condition variables being used by the pthread library, The overhead of the read/write lock used by the debugger. Sets to remove.
SPINLOOPTIMEThe number of attempts to acquire a lock in the state of CPU resource acquisition
YIELDLOOPTIMEThe number of times to yield CPU resources while holding lock
MALLOCMULTIHEAPSets up in a multi-threaded environment that uses a lot of malloc
AIXTHREAD_MUTEX_FASTAs an option to change the operating system's internal mutex_locking behavior. If the mutex_contention is severe, set it to ON to improve the performance. Can be represented. It is provided in AIX 5.2 and later.

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Summary

For stable operation of Altibase on the AIX operating system, kernel parameter settings and user environment settings must be performed in advance. If the setting is not performed properly, it should be noted that the problem can be caused by each limit value even though the system has sufficient resources.

Setting Examples

Kernel Parameters

Refer to the table below and set the appropriate kernel parameters. For reference, in AIX, some of the resource limit items are adjusted by changing kernel parameters.

ClassificationKernel ParameterRecommended ValueRemark
Posix AIOConfigure Defined Asynchronous I/OAvailableRequired under AIX 6.1
File Cachelru_file_repage0Considered under AIX6.1 (Requires lru_file_repage) File Cache
strict_maxclient0Considered under AIX6.1 (Requires lru_file_repage)File Cache
minperm10Considered under AIX6.1 (Requires lru_file_repage)
Resource limitationThe maximum number of PROCESSES allowed per userMore than the number of processes that can be running simultaneouslyCorresponds to max user process

User Resource Limits

Refer to the table below, if possible, set it to unlimited.

ClassificationDescriptionRecommended Value
data seg size(data)The maximum size of the process data areaunlimited
file size (fsize)The maximum size of the created fileunlimited
open files (nofiles)The maximum number of files that can be accessed by one process at the same timeunlimited
max memory size (rss)The maximum size of available memoryunlimited
max user processThe number of processes that can be created per userMaximum number of PROCESSES allowed per user

User Environment Variables

In the case of sh, bash, and ksh, examples of settings required environment variables using the environment setting file are as follows. In the case of csh, it is declared through a shell command such as setenv instead of export.

User Environment Variable Setting Examples

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