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Infor ERP LN 6.1
Users Guide for Kernel Tuning
Copyright © 2008 Infor
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Publication Information
Document code: U8752B US
Release: Infor ERP
Publication date: February 08
Table of Contents
Chapter 1 To tune the Operating System for Infor ERP LN .................................................. 1-1 Parallel processing..................................................................................................................... 1-2
Chapter 2 MS Windows configuration Settings..................................................................... 2-1 Switches in file C:\boot.ini .................................................................................................... 2-1 Optimize system for background services ........................................................................... 2-1 Configure Server service ..................................................................................................... 2-2 Winstation Heap Size........................................................................................................... 2-3
Chapter 3 Unix Kernel Parameters ......................................................................................... 3-1 Processes .................................................................................................................................. 3-2
NPROC................................................................................................................................ 3-2 Files ........................................................................................................................................... 3-3
NFILE................................................................................................................................... 3-3 NOFILES, SFNOLIM (SVR4), MAXFILES (HP), RLIM_FD_CUR (SUN), RLIM_FD_MAX (SUN)......................................................................................................... 3-4
Buffers........................................................................................................................................ 3-4 NBUF ................................................................................................................................... 3-5 NBUF (SVR4) ...................................................................................................................... 3-5 NHBUF ................................................................................................................................ 3-6
Shared memory ......................................................................................................................... 3-6 SHMALL .............................................................................................................................. 3-6 SHMMAX ............................................................................................................................. 3-7 SHMMIN .............................................................................................................................. 3-8 SHMMNI .............................................................................................................................. 3-8 SHMSEG ............................................................................................................................. 3-9
ii | Table of Contents
Semaphores............................................................................................................................... 3-9 SEMMAP ............................................................................................................................. 3-9 SEMMNI ............................................................................................................................ 3-10 SEMMNS ........................................................................................................................... 3-10 SEMMNU........................................................................................................................... 3-10 SEMUME ........................................................................................................................... 3-11
Messages................................................................................................................................. 3-11 MSGMAP........................................................................................................................... 3-11 MSGMAX........................................................................................................................... 3-12 MSGMNB........................................................................................................................... 3-12 MSGMNI ............................................................................................................................ 3-12 MSGSEG ........................................................................................................................... 3-13 MSGSSZ............................................................................................................................ 3-13 MSGTQL............................................................................................................................ 3-14
General kernel parameters ...................................................................................................... 3-14 MAXUSERS....................................................................................................................... 3-14 MAXUPROC, MAX-PROC-PER-USER ............................................................................. 3-14
Chapter 4 System Specific Tuning ......................................................................................... 4-1 Hewlett Packard – HPUX ........................................................................................................... 4-1
NBUF ................................................................................................................................... 4-1 BUFPAGES ......................................................................................................................... 4-1 DBC_MIN_PCT and DBC_MAX_PCT ................................................................................. 4-2
Hewlett Packard – Tru64 UNIX .................................................................................................. 4-2 FIFO-DO-ADDAPTIVE......................................................................................................... 4-3 UBC_MINPERCENT, UBC_MAXPERCENT, UBC_BORROWPERCENT and VM_UBCSEQSTARTPERCENT.......................................................................................... 4-3 GH_FAIL_IF_NO_MEM ....................................................................................................... 4-4 INSECURE_BIND................................................................................................................ 4-5 VM_SWAP_EAGER or /SBIN/SWAPDEFAULT .................................................................. 4-5 /DEV/TIMEDEV.................................................................................................................... 4-5
SUN / Fujitsu Siemens – Solaris ................................................................................................ 4-6 NBUF/NPROC ..................................................................................................................... 4-6
Table of Contents | iii
PT_CNT............................................................................................................................... 4-6 PRIORITY_PAGING/ FASTSCAN/ MAXPGIO .................................................................... 4-6
About this Guide
Before you install Infor ERP LN, check the OS kernel. Necessary changes must be made to avoid problems during the installation if multiple users try to enter the system, or at production. This document explains the kernel parameters that must be set on various platforms.
The following four chapters are included:
Chapter 1, “To tune the OS Kernel for Infor ERP LN,” describes the tasks how to adjust the underlying operating system Infor ERP LN.
Chapter 2, “MS Windows configuration settings,” describes the advised settings for the Windows 2003 environment.
Chapter 3, “UNIX kernel parameters,” lists the involved kernel parameters for the UNIX platform.
Chapter 4, “System-specific tuning,” lists additional tuning data for specific platforms.
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vi | Table of Contents
1 Chapter 1 To tune the Operating System for Infor ERP LN
This version of the Kernel Tuning Guide supplies the following information:
Behavior of the specific settings.
Kernel settings for Parallel Processing.
MS Windows 2003 settings.
These settings are valid only for Infor ERP LN. If you add other products, this can affect the system. If you do this, you must read the documentation of these products to find their particular kernel settings.
Database-specific settings are not added to this document. For information on the database-specific settings, refer to the official database documentation.
This document also describes the kernel and configuration parameters from several hardware platforms. The following platforms are specified in this document:
HP-UX.
IBM (pSeries/RS6000 and IBM Numa).
Compaq Tru64 Unix.
Solaris for the SUN and the Fujitsu Siemens platform.
MS Windows 2003.
AS/400 and OS/390 are not included, because the AS/400 kernel is self-tuning, and this is not necessary for an Infor ERP LN installation. OS/390 is too specific for this document.
1-2 | To tune the Operating System for Infor ERP LN
Parallel processing
In some batch sessions, parallel processing can be used to speed up the performance. When this feature is enabled, the job is spread over multiple bshells. If a batch session is configured to run with parallel bshells, the main program starts up more bshells to spread the load. Running with multiple bshells is only necessary when more than one CPU is available in the system. The communication protocol between the parallel bshells is based on message queues, which on MS Windows platforms is configured automatically. However, in most cases it needs to be set on UNIX.
The following guidelines and values are for UNIX kernels.
To get parallel processing running, the message queues must be configured in the kernel with at least the following settings:
Description Minimum value
Maximum message length (bytes) 256
Messages per message queue 1024
Size per message queue (bytes) 1024 * 256 = 262144
Number of message queues system wide 2 * #parallel bshells + 6
Messages system wide 1024 * (2 * #parallel bshells + 6)
The settings are based on the following:
The maximum number of parallel bshells running on all parallel sessions.
Only used for parallel processing. In situations where other products also make use of message queues, use the sum of the numbers.
If these settings have values below the default OS values, use the default OS values.
2 Chapter 2 MS Windows configuration Settings
The MS Windows platform’s kernel is completely different compared to a UNIX kernel. To optimize performance, some important settings are required. This Chapter discusses the MS Windows 2003 settings.
Switches in file C:\boot.ini
The following switches can be needed by Infor ERP LN:
/PAE With this, the system can use more than 4GB of memory. MS Windows 2003: With Advanced Server, 32GB of memory can be used. With Datacenter, 64 GB of memory can be used.
/3GB With this, the user’s virtual memory address space can be enlarged from 2GB to 3GB.
Optimize system for background services
Description
If you use a system as server, you must spread the CPU load on all tasks. Foreground processes must not get special priority over background applications.
Setting
MS Windows 2003: Go to System Properties -> Advanced -> Performance -> Performance Options -> Advanced: - Process scheduling, Background services - Memory usage: Programs
2-2 | MS Windows configuration Settings
Configure Server service
Description
MS Windows 2003 can tune the server for the job it must do. Infor ERP LN needs a server whose memory is optimized for distributed applications that perform their own memory caching.
Setting
Go to Network and Dial-up Connections -> Local Area Connection -> File and Printer Sharing for Microsoft Networks Properties. Select Maximize throughput for network applications.
MS Windows configuration Settings | 2-3
Winstation Heap Size
Description
MS Windows 2003 maintains registry settings to control the heap size for desktops associated with non-interactive window stations. Some non Infor ERP LN programs changes this value during installation. Only change this value if you experience problems.
Change the HEAP SIZE value directly in the registry. The registry key is in HKEY_LOCAL_MACHINE:
\System\CurrentControlSet\Control\Session Manager\SubSystems
It has the value-name Windows.The value-name consists of a list of values. The one we are interested in is SharedSection=1024,3072. The SharedSection value can have 4 values. Usually, the last two values are not specified and defaults are used.
Settings
If you experience problems with Infor ERP LN, try to increase or add the third value. However, you must be careful. Increasing this value makes it possible that more processes can be started. You must try to increase this value into steps of 512, 1024, 2048, 3072 or 4096, such as the following:
SharedSection=1024,3072,2048
2-4 | MS Windows configuration Settings
Tuning
The problem observed, when this value is too low, is as follows:
Connection problems to Infor ERP LN server, or MS SQL Server.
Popup messages on console from sort.exe with message “User32.dll or Kernel32.dll Fails to Initialize”
Note: It is known that this value conflicts with the use of Terminal Services. Therefore, do not use Terminal Services on the Infor ERP LN server.
On some MS Windows 2003 servers, running older hardware and setting this value too high, to 2048 or higher, will result in the server no longer booting. Therefore, fall back on the last known good configuration.
3 Chapter 3 Unix Kernel Parameters
This chapter describes the different generic UNIX kernel parameters. In general, these parameters can be split into the following categories:
Processes.
Files.
Buffers.
Shared memory.
Semaphores.
Messages.
General kernel parameters.
Hardware-specific kernel parameters.
Except for the hardware-specific kernel parameter category, all other parameters are discussed in this chapter. The specific hardware parameters are discussed in the next chapter.
The parameter name mentioned in the next sections is the common name. The parameter names can have slightly different names on each platform, but must be recognizable.
3-2 | Unix Kernel Parameters
A number of variables are used in the formulas. Their definitions are as follows:
#connected user: Maximum number of connected users on the system. Those users do not have to be active, but still consume system resources. It is assumed each end user is only logged on once. Increase the number of connected users with the extra logons of each end user.
#additional database drivers: Extra database drivers needed to access multiple database instances at the same time. Each connected user normally uses one database instance and one database driver. In certain situations, this value is larger than zero.
Processes
These parameters are related to the number of processes that run on an Infor ERP LN environment. Dependent on the configuration, connection method, and other variables, these parameters must be set.
NPROC
Description
Specifies the maximum number of processes that can run system-wide at once.
Value
It depends on the configuration as to how you tune the NPROC parameter:
2-tier 3-tier application server
3-tier database server
NPROC 5 * #connected users + 512
* #connected users + 512
2 * #connected users + 512
These settings are based on the following:
Each connection contains a bshell, a database driver, an audit driver, a database backend process, and one additional process. In case of special circumstances, the number of processes must be increased.
Each user connects to Infor ERP LN through Webtop or the Worktop.
Each user runs one database driver. In case of multiple database drivers, the number of processes must be increased with the following:
Unix Kernel Parameters | 3-3
2-tier 3-tier application server
3-tier database server
NPROC = NPROC +
2 * #additional database drivers * # connected users
#additional database drivers * # connected users
#additional database drivers * # connected users
The 512 additional processes is based on a common environment with a
database. In case of additional products, the total amount of processes must be increased.
Connected Users Tuning
When UNIX error 11 occurs: “No more processes.”, the value of NPROC should be increased.
The current and maximum number of processes can be found in the column proc-sz, from the sar -v output.
Note: On some UNIX systems the following extra command is started by the inetd:
sh –c /.../ipc_boot6.2…
To prevent this, give the user a korn shell (/usr/bin/ksh) as a login shell in /etc/passwd, instead of a born shell (/bin/sh).
Files
The file parameters contain all types of parameters related with files. Infor ERP LN reads a great deal of files, but closes them almost directly after reading. Therefore, most of the values can be kept small.
NFILE
Description
The value of this parameter specifies the number of files that can be opened system-wide simultaneously.
3-4 | Unix Kernel Parameters
Value
Infor ERP LN uses a couple of files simultaneously. The maximum number of open files at a certain moment that will be opened are as follows:
NFILE >= 16* #connected users + 1024(with a minimum of 1024)
For OS tasks and database activities, it is safe to add another 1024.
Tuning
The number of this parameter must be increased when error 23 appears: File table overflow. The current and maximum number of open files can be found in the column file-sz, from the sar -v output.
NOFILES, SFNOLIM (SVR4), MAXFILES (HP), RLIM_FD_CUR (SUN), RLIM_FD_MAX (SUN)
Description
Specifies the maximum number of files that can be opened per process.
Value
Unlike the database, Infor ERP LN does not use numerous files at the same time. A save value is as follows:
NOFILES >= 256
Tuning
The number of this parameter must be increased when error 24 appears: Too many open files.
Buffers
The buffer parameters specify how much memory must be reserved for I/O buffering. For most Infor ERP LN environments, the database activity, not the Infor ERP LN processes, generates almost all I/O.
Unix Kernel Parameters | 3-5
NBUF
Description
Specifies the number of system buffers available for block I/O and data I/O.
Value
Infor ERP LN does very little I/O. In general, 5% of the internal memory is sufficient for system buffers. Incase a database is also running on the system, take the amount of transferred I/O of that database into account. Incase of a database with raw devices, 5% is still sufficient. Otherwise. in most cases, the value of NBUF must be increased to 10% of the internal memory. The number of buffers must be set low, because each database can reserve memory for database buffers. It is better to allocate buffers in the database than to use that memory for UNIX buffer cache.
If the system has a high I/O to disk, but has a lot of memory on disk, then the NBUF must not be set to 10% of the internal memory, but to a much smaller value, such as 5%.
Tuning
If the system suffers due to less memory, such as paging or swapping, check if NBUF can be reduced.
If there is more than enough memory in the system, check if increasing NBUF makes sense. On several systems, the I/O can be monitored with sar –b and sar –u.
NBUF (SVR4)
Description
In UNIX SVR4, buffers only contain inode, superblock(s), and file header information, but not file data. The actual file data is stored in pages of virtual memory. The NBUF parameter specifies the number of system buffer headers available for block I/O.
Value
The value for NBUF can be set to the default value, such as 100.
3-6 | Unix Kernel Parameters
Tuning
On several systems, the I/O can be monitored with sar –b and sar –u.
NHBUF
Description
Specifies the number of hash table entries that can be allocated in the system.
Value
The value of NHBUF depends on the value of NBUF. By default, it can be set to the following:
NHBUF = 1/5 * NBUF
The value of NHBUF must be a power of 2.
Shared memory
Infor ERP LN uses shared memory to share data definitions and objects. Data stored in the shared memory can be shared between users. It improves performance, because a data definition or object that is stored in shared memory does not need to be read from disk. It saves memory because the object or data definition is only read once, instead of multiple times in memory. The shared memory parameters are specified in the $BSE/lib/shm_param file. Values of SHM_BUFSIZE and SHM_MAXMEM are closely related to the parameters SHMMAX and SHMMNI. You must make few shared memory segments for Infor ERP LN. Setting SHMMAX to 16MB or higher is recommended.
SHMALL
Description
Specifies the maximum number of shared memory text segments that can be created.
Value
SHMALL = SHMMNI
Unix Kernel Parameters | 3-7
Tuning
Increase when error 24 occurs on a shared memory text segment.
SHMMAX
Description
Specifies the maximum size of a shared memory segment that can be created in bytes. Several shared memory segments of this size can be created per process in an environment.
3-8 | Unix Kernel Parameters
Value
The minimum value for SHMMAX = 4194304 (4 MB). You must set SHMMAX to at least 16MB:
SHMMAX = 16777216
Incase a database also runs on the same system, take the recommended value from the database vendor. Usually, it will be between 60% and 100% of internal memory.
Tuning
Increase in case of error 22.
SHMMIN
Description
Specifies the minimum size of a shared memory segment in bytes.
Value
To get all programs to create a shared memory segment, specify this parameter to the smallest value:
SHMMIN = 1
SHMMNI
Description
Specifies the maximum number of shared memory identifiers that can be created system-wide.
Value
The value of SHMMNI must be dependent on the number of Infor ERP LN environments, databases, and other programs that use shared memory. In a single Infor ERP LN, setting the single database environment to 30 is sufficient.
Tuning
The number of shared memory segments can be monitored with ipcs –m. If the number of shared memory segments come close to SHMMNI, you must
Unix Kernel Parameters | 3-9
increase the parameter to prevent later problems. To specify an optimal value, check all other resources that use shared memory. Increase when error 28 occurs.
SHMSEG
Description
Specifies the maximum number of shared memory segments that can be created by a process.
Value
The number of shared memory must be kept as small as possible. The following setting is sufficient for SHMSEG in most situations:
SHMSEG = 30
Tuning
Incase of a badly tuned environment, this parameter can run out of its value. If so, check the value of SHMMAX and Infor ERP LN, or database parameters before increasing this value. Increase when error 24 occurs.
Semaphores
Semaphores are used to protect programs, shared memory, and message queues. In Infor ERP LN, semaphores are used when something must be written in shared memory with Java integrations with parallel processing.
SEMMAP
Description
Specifies the number of entries in the control map used to manage semaphores. This map is used to keep track of free areas in the system pool of semaphores.
Value
Set the number of SEMMAP 2 higher than SEMMNI:
SEMMAP = SEMMNI + 2
3-10 | Unix Kernel Parameters
Tuning
Increase when error mfree map overflow occurs.
SEMMNI
Description
Specifies the maximum number of semaphore identifiers in the kernel. This is the number of unique semaphore sets that can be active at any given time.
Value
Usually, it is safe to set this value to 128.
Tuning
Increase when error 28 occurs.
SEMMNS
Description
Specifies the maximum number of semaphores permitted in the system.
Value
Keep SEMMNS the same number as SEMMNI:
SEMMNS = SEMMNI
Tuning
The number of semaphores can be monitored with ipcs –sb.
SEMMNU
Description
Specifies the number of undo structures in the system.
Value
Keep SEMMNU the same number as SEMMNI:
Unix Kernel Parameters | 3-11
SEMMNU = SEMMNI
Tuning
Increase when error 28 occurs.
SEMUME
Description
Specifies the maximum number of undo entries per undo structure. Each undo entry represents a semaphore that has been modified with the undo flag specified in the semop(2) system call.
Value
Keep the default value for SEMUME, such as the following:
SEMUME = 10
Tuning
Increase when error 22 occurs.
Messages
Messages can be used for communication between processes/parallel processing. Usually, communication between processes by message queues is not the most optimal performing method. Therefore, it can be skipped for configuring message queues in the kernel. If message queues (m) are used in the $BSE/lib/ipc_info, see if it can be changed into pipes (p).
MSGMAP
Description
Specifies the number of entries in the control map used to manage message segments. Each entry in this map represents a free area in the message buffer area.
Value
The default value can be used for this parameter, such as the following:
3-12 | Unix Kernel Parameters
MSGMAP = 100
Tuning
Increase when error mfree map overflow occurs.
MSGMAX
Description
Specifies the maximum size of a message in bytes.
Value
Because the messages from the parallel processing are relative small, a maximum size of 4096 is sufficient for Infor ERP LN and most of the time for other products. MSGMAX must be lower than MSGMNB.
MSGMAX = 4096
MSGMNB
Description
Specifies the maximum length, in bytes, of a message queue.
Value
The maximum number of bytes in a message queue is 262144. Therefore, MSGMNB must be set to at least this value:
MSGMNB >= 262144
Tuning
The number of bytes in a message queue can be checked with ipcs –qo.
MSGMNI
Description
Specifies the maximum number of message queues that can be used system-wide.
Unix Kernel Parameters | 3-13
Value
The number of message queues needed for Infor ERP LN is relatively small. On most systems, 64 message queues is sufficient. For more information on how to calculate the number of message queues, refer to Chapter 1 “To tune the OS kernel for Infor ERP LN.”
MSGMNI = 64
Tuning
Increase when error 28 occurs.
MSGSEG
Description
Specifies the number of message segments permitted on the system. Each message on a message queue consists of one or more message segments. The size of each segment is specified by the MSGSSZ parameter.
Value
This parameter can be set to the default value, such as the following:
MSGSEG = 1024
MSGSSZ
Description
Specifies the size, in bytes, of a message segment. Each message consists of a nearby set of message segments large enough to hold the text of the message.
Value
This parameter can be set to the default value, such as the following:
MSGSSZ = 8
3-14 | Unix Kernel Parameters
MSGTQL
Description
Specifies the maximum number of message headers that is the maximum number of open messages.
Value
Keep this parameter equal to MSGMNI:
MSGTQL = MSGMNI
General kernel parameters
MAXUSERS
Description
This parameter is used for a lot of kernel parameters to calculate default values. Parameters not explicitly specified can get a value through this internal formula.
Value
Set the value of MAXUSERS to the number of expected connected users at any time.
MAXUSERS = #connected users + 10
Tuning
Tune to the number of users after changing, such as the number of licenses.
MAXUPROC, MAX-PROC-PER-USER
Description
This parameter describes the number of processes enabled to run under a certain user id.
Unix Kernel Parameters | 3-15
Value
The value depends on the configuration. Usually, the default value is fine. However, there are some exceptions when this parameter must be increased, such as the following:
Multiple users run under the same userid. This often occurs before going live. Several users logon under the id of bsp. Together, they generate a lot of processes.
If BSE_REM is used, some customers prefer to run all users as one particular remote user, such as the user bsp. In that case, the number of processes per user must be increased.
On a three-tier database server, all processes run with the process ID of the database owner on several databases. Therefore, you must increase the number of processes per user.
The above situations can cause problems on this parameter. If any of these situations occur, calculate the maximum number of needed processes per user and tune the parameter.
Tuning
If you run out on processes, increase the value of NPROC, or lower the value of MAXUPROC, MAX-PROC-PER-USER when possible.
4 Chapter 4 System Specific Tuning
This chapter describes the system specific tuning parameters per platform.
Hewlett Packard – HPUX
NBUF
Value
This parameter must be set to 0, because it is obsolete.
BUFPAGES
Description
Specifies the number of pages in the file system buffer cache. The description and calculation of the non-HP NBUF parameter is applicable to this parameter.
Value
To set the field to Dynamic, specify the following:
BUFPAGES = 0
If more control on this parameter is needed, a fixed value can be specified. If set to 0, the lower and upper boundary can be specified with the parameters DBC_MIN_PCT and DBC_MAX_PCT.
4-2 | System Specific Tuning
Tuning
Depends on the usage of the system. If Infor ERP LN is the only application on the system, it can be set to 0.
DBC_MIN_PCT and DBC_MAX_PCT
Description
Specifies the minimum and maximum percentage of memory used for buffer pages. If BUFPAGES is set to 0, these parameters will be taken for a lower and upper boundary for the buffer pages.
Value
The value for these parameters is dependent on the configuration. System usage is required to use these parameters. Therefore, watch the memory usage over a period of time and tune the parameters to the system behavior.
Hewlett Packard – Tru64 UNIX
Note: All described Tru64 UNIX kernel parameters are located in /etc/sysconfigtab.
You can no longer change one or more kernel parameters by editing the sysconfigtab file with an editor. Either create a stanza file for these subsystem(s)/parameter(s) and enter these (new) values using sysconfigdb, Alternatively, use a dxkerneltuner if you use an X-based station.
For more information about adding/changing kernel parameters, refer to the appropriate manual pages of the following:
sysconfigtab. sysconfig. sysconfigdb. stanza. dxkerneltuner.
System Specific Tuning | 4-3
FIFO-DO-ADDAPTIVE
Description
In Tru64, pipes are optimized for the traditional UNIX piping mechanism. To change the IPC behavior from tuned for throughput (bandwidth) to low latency messaging, the parameter fifo-do-adaptive has been introduced.
Value
It needs to be set to zero for Infor ERP LN:
vfs: fifo-do-adaptive = 0
UBC_MINPERCENT, UBC_MAXPERCENT, UBC_BORROWPERCENT and VM_UBCSEQSTARTPERCENT
Description
UBC_MINPERCENT and UBC_MAXPERCENT specifies the minimum and maximum percentage of memory used for buffer pages. UBC_BORROWPERCENT specifies the amount of memory from which memory is borrowed from the virtual memory subsystem. If NBUF is set to 0, these parameters will be taken for a lower and upper boundary for the buffer pages. UBC_BORROWPERCENT must be equal or larger than UBC_MINPERCENT, and smaller or equal than UBC_MAXPERCENT.
Value
The values for these parameters are dependent on the configuration. Ongoing performance analyzing will be necessary to find the correct values. For a typical environment, where the database is on top of (AdvFS) file systems, the values may look like the following:
vm: ubc_minpercent = 5 ubc_maxpercent = 10 ubc_borrowpercent = 8 vm_ubcseqstartpercent = 7
With Tru64 UNIX V5.0A, AdvFS supports direct asynchronous I/O. Starting with Oracle 8.1.7, the RDBMS will default in using this feature. Open the database files with the O_DIRECTIO flag when on top of AdvFS and running on Tru64 UNIX V5.0A or above. Therefore, although AdvFS is used, I/Os will not be buffered in system buffer cache. This gives a new approach to tuning UBC when using this feature. Since these I/Os will not be buffered, the
4-4 | System Specific Tuning
values can be increased to allow the use of more UBC for other purposes. The following are examples of typical values:
vm: ubc_minpercent = 10 ubc_maxpercent = 40 ubc_borrowpercent = 20 vm_ubcseqstartpercent = 15
Long-term measurement may be needed to find the correct settings for a particular configuration. Through a patch, previous versions of Oracle supports asynchronous direct I/O. Contact Oracle support for the appropriate Oracle versions and the availability of these patches.
GH_FAIL_IF_NO_MEM
Description
If enabled (1), it specifies an error is returned by the shmget function when granularity hints are in use and insufficient memory is allocated through gh_chunks. Under certain conditions, this may result in a hang of the RDBMS.
If disabled (0), the shmget function will not return an error. Instead, the memory segment will be allocated from system pageable memory.
Value
For a typical environment, the values can be as follows.
vm: gh_fail_if_no_mem = 0
System Specific Tuning | 4-5
INSECURE_BIND
Description
When Oracle Parallel Server (OPS), or Informix with IPC streams (ipcstr) is used, it is necessary to enable insecure binding to sockets.
Value
For a typical environment, the values can be as follows.
generic: insecure_bind = 1
VM_SWAP_EAGER or /SBIN/SWAPDEFAULT
Description
When the minimum amount of swap space is required, it is necessary to switch to lazy, or deferred, swap mode. Note that 512MB internal memory needs 1GB of swap space. More than 1GB of internal memory needs a one to one relationship regarding the size of swap space.
Value For a typical environment, the values can be as follows: generic: vm_swap_eager = 0
/DEV/TIMEDEV
Description
When Oracle timed statistics is used, much system time can be used, because of the large number of calls to the gettimeofday function. Create a special file to use another mapping mechanism to the kernel’s date and time structures. Use the following command:
mknod /dev/timedev c 15 0
4-6 | System Specific Tuning
SUN / Fujitsu Siemens – Solaris
NBUF/NPROC
Do not set NBUF and NPROC on Solaris. This can cause problems.
PT_CNT
Description
Specifies the number of pseudo terminals. Refer to “General Kernel Parameters” in Chapter 3, “UNIX Kernel Parameters.”
After changing this parameter, the devices have to be generated. This can be done through the command boot –r.
PRIORITY_PAGING/ FASTSCAN/ MAXPGIO
Description
These parameters increase performance and influence the priority paging mechanism. After changing these parameters, a process memory page gets higher priority than a file system buffer page.
Value
For a typical environment, the values can be as follows:
PRIORITY_PAGING = 1 FASTSCAN = 131072 MAXPGIO = 16384