i'm wondering if there is a way to determine minimum memory requirement for AIX kernel and OS functions? We use memdetails script from perfpmr package to see actual memory allocation, for example like this:
Code:
===========================================================================
Memory accounting summary | 4K Pages | Megabytes
----------------------------------------------------|----------|-----------
Total memory in system | 16842752 | 65792.00
Total memory in use | 14972379 | 58485.85
Kernel identified memory (segids,wlm_hw_pages) | 3498632 | 13666.53
Kernel un-identified memory | 20694 | 80.83
Fork tree pages | 0 | 0.00
Large Page Pool free pages | 0 | 0.00
Huge Page Pool free pages | 0 | 0.00
User private memory | 3195171 | 12481.13
User shared memory | 3918957 | 15308.42
User shared library text memory | 143312 | 559.81
Text/Executable code memory in use | 8841 | 34.53
Text/Executable code memory not in use | 266575 | 1041.30
File memory | 3171274 | 12387.78
User un-identifed memory | 748923 | 2925.48
---------------------- | |
Total accounted in-use | 14972379 | 58485.85
Free memory | 1870373 | 7306.14
---------------------- | |
Total identified (total ident.+free) | 16073135 | 62785.68
Total unidentified (kernel+user w/ segids) | 769617 | 3006.31
---------------------- | |
Total accounted | 16842752 | 65792.00
Total unaccounted | 1213075 | 4738.57
You can see there is still some free memory but also that AIX kernel uses 13 GB on a 64 GB system. How can i tell what will be the maximum kernel memory? We measured this after reboot and starting the applications, kernel took only 2 GB but during 4 months it gradually grew to 13 GB. What would happen if i configured applications to take let's say 60 GB of memory. Will AIX handle that and live with 4 GB for kernel or will it start trashing until reboot is necessary? I can't seem to find any minimum OS requirements so i don't really know how much memory is available to applications. There are no exact figures, everyone only mentions it depends on running services, devices, network etc. etc. but there is no hint of how to calculate the maximum potential usage alltogether.
Anyone has dealt with this before that could help? I have been trying to apply for AIX Performance tuning training for last 3 years so i could ask these questions but since i was always the only one who applied, the course was never opened
Hello,
I'm using a unix server (HP rp2450) which has : 2 Go RAM memory and 4 Go swap.
Here is the result of vmstat -n command :
$ vmstat -n
VM
memory page faults
avm free re at pi po fr de sr in sy ... (5 Replies)
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Hi
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Hi,
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Discussion started by: c3rb3rus
8 Replies
LEARN ABOUT HPUX
nflocks
nflocks(5) File Formats Manual nflocks(5)NAME
nflocks - maximum number of file locks
VALUES
Failsafe
Default
The default value is computed at runtime and depends on the amount of physical memory on the system. For small memory systems (less than
1GB), the default is 1200. For systems with more than 1GB of memory, the default is 4096, or 4K.
Allowed values
The minimum value is 50. The maximum value is 0x1000000.
Specify a positive integer value.
DESCRIPTION
The tunable represents the maximum number of file locks that are available system-wide.
Who Is Expected to Change This Tunable?
This tunable should be changed on systems expected to run applications with large number of file locks. When changing this number note
that one file may have several locks, and databases that use or may need an exceptionally large number of locks.
Restrictions on Changing
This tunable is dynamic (tuning will take effect immediately on the running system). When the value of is dynamically tuned it cannot be
set to a value lower than the current number of file locks in the running kernel.
When Should the Value of This Tunable Be Raised?
The value should be increased when large numbers of file locks are expected to be used simultaneously.
What are the Side Effects of Raising the Value?
The kernel allocates a portion of memory proportional to the new value of and frees memory proportional to the old value. Additional mem-
ory is consumed as new locks are created.
When Should the Value of This Tunable Be Lowered?
The value can be lowered to limit the number of available file locks on a system and reduce memory consumption.
What are the Side Effects of Lowering the Value?
The kernel allocates a portion of memory proportional to the new value of and frees memory proportional to the old value. Additional mem-
ory may be released to the system to be used for other purposes if the usage was ever higher than this new value.
What Other Tunable Values Should Be Changed at the Same Time?
None.
WARNINGS
Setting to the maximum value(0x1000000) will result in a large memory allocation (~.5GB). A request to change the value of will fail with
set if there is either not enough free memory or the remaining free memory would be so small as to potentially hinder system performance.
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its meaning changed in future releases of
HP-UX.
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parameter values. After installation,
some tunable parameters may no longer be at the default or recommended values. For information about the effects of installation on tun-
able values, consult the documentation for the kernel software being installed. For information about optional kernel software that was
factory installed on your system, see at
AUTHOR
was developed by HP.
SEE ALSO kctune(1M), sam(1M), gettune(2), settune(2), fcntl(2), lockf(2).
Tunable Kernel Parameters nflocks(5)
02-05-2014
AIX 6.1 memory tuning
