AIX 6.1 memory tuning Post: 302887193

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Operating Systems AIX AIX 6.1 memory tuning Post 302887193 by -=XrAy=- on Thursday 6th of February 2014 09:09:48 AM

02-06-2014

Registered User

Quote:

Originally Posted by dzodzo

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 do not know a formula too calculate the minimum for kernel memory.
As you said the memory usage will grow with time and usage (mbufs, inode cache, jfs bufstructs, etc.) and the increase depends on the maximum installed memory. The Kernel used pinned memory (vmstat -v) and if your application with 60GB also used pinned memory, your server will crash/panic if there are no more memory which can be pinned. That happened to us after two weeks with a wrong Informix memory configuration. The other way the server starts to swap out (paging space) and the performance slows down.

Regards

-=XrAy=-

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vxfs_ifree_timelag

vxfs_ifree_timelag(5)						File Formats Manual					     vxfs_ifree_timelag(5)

NAME

       vxfs_ifree_timelag - VxFS inode free time lag (specifies the minimum time to be spent on a freelist)

SYNOPSIS

VALUE

       Specify an integer value.

   Minimum
       None

   Maximum
       None

   Default
       0

DESCRIPTION

       In  VxFS, the unused inodes are put on a freelist. The memory space for this unused inode is freed if it stays on the freelist for a speci-
       fied amount of time. The tunable specifies the minimum amount of time should spend on a freelist before its memory space is freed. The time
       is specified in seconds.

       is a dynamic tunable. Any changes to take effect immediately.

EXAMPLES

       Change the value of to 2400 seconds:

WARNING

       Incorrect tuning of may adversely affect system performance.

       All  HP-UX  kernel tunable parameters are release specific.  This parameter may be removed or its meaning may change in the 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

SEE ALSO

       kctune(1M), vx_maxlink(5), vx_ninode(5), vxfs_bc_bufhwm(5).

							     Tunable Kernel Parameters					     vxfs_ifree_timelag(5)