This section describes the procedures for estimating the HP-UX OS parameter values (or kernel parameter values). If OS parameter values are too small, HiRDB may not function correctly. Table 21-3 shows the guidelines for the HP-UX OS parameter values.
Table 21-3 Guidelines for the AIX 5L OS parameter values
OS parameter | Guideline for value |
---|
data_hard | The parameter default value is -1 (unlimit). Do not specify this if there is no particular reason to do so. |
stack_hard | The parameter default value is -1 (unlimit). Do not specify this if there is no particular reason to do so. |
nofiles | HiRDB calculates and sets this value, so you do not need to specify it. |
nofiles_hard | The parameter default value is -1 (unlimit). Do not specify this if there is no particular reason to do so. |
maxuproc | Specify at least MAX(value of pd_max_server_process + e, 512). However, if this value is less than the value required by another program that runs on the server machine, specify the higher value. |
EXTSHM environment variable | For the 32-bit mode, specify ON. For the 64-bit mode, specification of this parameter is not needed. |
- e: Maximum number of concurrently executable commands (including utilities)
- Note
- The maximum number of files that can be opened in the system concurrently can be controlled by maxuproc
nofiles
number of fixed licenses. - The maximum number of users who can log in to the system can be controlled by the number of fixed licenses.
- The maximum number of processes that can execute concurrently in the entire system can be controlled by maxuproc
number of fixed licenses.
- Organization of this section
- (1) Specifying parameters unique to AIX 5L
(a) Specifying environment variables
For AIX 5L, you need to specify the following environment variables in the system common definition.
- EXTSHM
In 32-bit mode, you must set ON, which indicates an unlimited number of shared memory areas in processing space. For 64-bit mode, you do not specify (you omit) putenv EXTSHM ON to enable the page fix functionality of the OS when you use the page fix facility of shared memory. The following table lists the EXTSHM environment variable specification formats for address mode.
Address mode | Page fix facility of shared memory# | Specification format for EXTSHM environment variables |
---|
32-bit mode | -- (not supported) | putenv EXTSHM ON |
64-bit mode | Used | Not specified |
Not used | -- (does not need to be specified) |
- #
- The page fix facility of shared memory is used when you specify fixed in the pd_shmpool_attribute operand or pd_dbbuff_attribute operand. For details, see pd_shmpool_attribute operand or pd_dbbuff_attribute operand in the manual HiRDB Version 8 System Definition.
- PSALLOC
Specify early, which indicates that the required paging space is to be allocated immediately. You also need to specify NODISCLAIM at the same time. However, useless paging space might still occur.
- NODISCLAIM
Specify true, which prevents nodisclaim() from being issued as the method of processing a free() call.
- LDR_CNTRL
- For 32-bit mode, specify this variable so that a larger data area than the standard kernel partitioning can be handled. Specify MAXDATA=0x40000000. This variable is not required for 64-bit mode.
- CORE_NOSHM
Specify "" to exclude the shared memory area in the core file, which is output when a process failure occurs. For details, see (d) Restricting the core file output information.
(b) Notes on the /etc/security/limits file specification values
Root users and HiRDB administrators must pay attention to the following specification values:
- data
An error occurs when the process heap area exceeds the limit value. If this limit value is not required, specify -1 (unlimited).
- fsize, fsize_hard
An error occurs when the file size exceeds this limit value. If this limit value is not required, specify -1 (unlimited).
(c) Specifying the Virtual Memory Manager (VMM) tuning parameters
Specify the following parameters when using specific facilities. You can set the VMM parameters using the vmo command (AIX 5L 5.2 and later) or vmtune command (AIX 5L 5.1) of AIX 5L. For details about the vmo and vmtune commands, see the documentation for AIX.
- v_pinshm
This parameter enables page fixing for shared memory segments. To fix shared memory pages used by HiRDB, specify 1 for this parameter. For details about how to fix shared memory pages used by HiRDB, see pd_shmpool_attribute operand or pd_dbbuff_attribute operand in the manual HiRDB Version 8 System Definition.
- maxpin
This parameter specifies the maximum percentage of page-fixed real memory. When you fix shared memory pages used by HiRDB, specify this parameter so that the real memory size within the percentage specified in this parameter is larger than the total size (including the size of paged memory fixed by the OS) of all page-fixed memory on the machine, including the size of the page-fixed HiRDB shared memory. For details about how to fix shared memory pages used by HiRDB, see pd_shmpool_attribute operand or pd_dbbuff_attribute operand in the manual HiRDB Version 8 System Definition.
(d) Restricting the core file output information
In AIX 5L V5.2 or AIX 5L V5.3, specify the following parameters to exclude the shared memory area in the core file that is output when a process failure occurs.
- Setting contents
- HiRDB administrator's environment variable (k shell)
- $ export CORE_NOSHM=
- System common definition
- putenv CORE_NOSHM ""
- Assumptions
- The OS used is AIX 5L V5.2 ML4 (IY56578) or later or AIX 5L V5.3.
- The fullcore parameter of the system attribute (sys0) is true.
- Notes
- HiRDB automatically sets fullcore to true during registration to the OS (when the pdsetup command is entered).
The fullcore parameter may have later been be reset to false with an OS command; make sure that the current fullcore parameter is true.
- Do not specify this environment variable CORE_NOSHM setting in /etc/environment.
(e) Notes on bogging down of programs due to high I/O load on the JFS/JFS2 file system
Execution of programs that send requests to the JFS/JFS2 file system for large output can cause the performance of system disk I/O to degrade. Programs such as pdcopy, or the compress, cp, and dd commands for large size files can cause programs running on the same system to stall for up to 20 to 30 seconds.
In particular, if the system operates with a cluster configuration that uses HA monitor or HACMP to monitor system response time, system switchover might occur.
To minimize this problem, you can equalize the write request frequency from application programs by setting an OS parameter for the system parameter (sys0). By specifying the following OS parameters, you can control I/O requests so that large numbers of I/O requests not completed for writing to the disk device do not accumulate in the file cache.
OS parameters | Guide to specification value# |
---|
maxpout | 33 |
minpout | 16 |
- #
- The optimum setting value of the maxpout/minpout parameter depends on the system configuration or I/O characteristics of applications.
- Therefore, it is effective to set a value listed in the above table and increase the value until application I/O performance is acceptable.
- For details about the maxpout/minpout parameter setting values, see thedocumentation for the OS.