Memory full Post: 302625791

Sponsored Content

Operating Systems AIX Memory full Post 302625791 by rbatte1 on Wednesday 18th of April 2012 09:45:56 AM

04-18-2012

Moderator

Remember that the OS will keep the memory full. You should concentrate on the paging space usage more. You have little relative to real memory (about 10%) where most people will run with at least double paging space to real memory (or allocated memory for an LPAR). 100% full in itself is not a problem. It doesn't cause a performance loss unless you end up paging. A "full" page in memory can still be counted even if it is not in use. It's just there in case it is re-requested.

A requirement for a new memory page will overwrite an obsolete one. If all the memory pages are marked as in-use, then the last recently referenced page is moved to disk (I/O wait) and the real page re-used.

I doubt you have more that /dev/h6 assigned for paging (issue lsps -a) so you can't easily see what paging space is actually marked as required. Over version 6 of AIX, the paging space is cleared when the owning process ends. For version 5, you can (if you have more than one paging space) issue a swapoff command which will work through the names paging space, moving 'live' pages to any remaining paging space. You can then run swapon and then do the same with the other paging spaces.

The time you need to worry is if you are seeing the server in I/O wait and lots of paging activity. Use vmstat to spot this. You are looking at the pi and po columns. Large numbers tells you that you have a problem. We had this recently and from using ps -el|sort -n +9 we could see the biggest memory allocation process and then had to work out what they were. You may need to check the column being sorted. It is the SZ column.

We determined that the Cobol written application was not releasing memory and indeed increased it every time certain routines ran, and again and again if they ran again in the process's life. A small coding change later helped tremendously.

I hope that this calms your fears. After that, you are into purchasing memory I'm afraid, most often in pairs of cards, e.g. 2x4Gb card.

To add another paging space there are smit panels to help you under "System Storage Management (Physical & Logical Storage)" or you can read the mkps and chps manual pages.

I hoep that this helps, but please write back if you are still stuck.

Robin
Liverpool/Blackburn
UK

This User Gave Thanks to rbatte1 For This Post:

rbatte1

View Public Profile for rbatte1

Visit rbatte1's homepage!

Find all posts by rbatte1

9 More Discussions You Might Find Interesting

1. Filesystems, Disks and Memory

Memory full (waiting)

Hi When I launch topas I have this result I have a memory problem. I don't know how see the process which waiting. How can I do that? Thanks all!!!

2. Shell Programming and Scripting

memory full warning message

Hi I wrote a script #!/usr/bin/ksh #set -x for fs in `df -k|awk '{print $1}'|sed -n "3,14 p"` do x=`df -kl | grep $fs | awk '{ print $5 }'` y=50% if then message="File System `df -k |grep $fs |awk '{print $6\", \"$5}'`...

3. Linux

my box can't see full memory

Hi I'be recently installed Virtouzzo on Centos 5 on 16GB box , but the system could only see 4 GB of RAM, I installed the package kernel-PAE, but the virtuozzo kernel still can't see the full memory. even the kernel system can see 16GB of RAM is there any idea bout that ? Thanks

4. Solaris

How to find Total and Free Physical Memory and Logical Memory in SOLARIS 9

Hi, Im working on Solaris 9 on SPARC-32 bit running on an Ultra-80, and I have to find out the following:- 1. Total Physical Memory in the system(total RAM). 2. Available Physical Memory(i.e. RAM Usage) 3. Total (Logical) Memory in the system 4. Available (Logical) Memory. I know...

5. Programming

How to deal with lots of data in memory in order not to run out of memory

Hi, I'm trying to learn how to manage memory when I have to deal with lots of data. Basically I'm indexing a huge file (5GB, but it can be bigger), by creating tables that holds offset <-> startOfSomeData information. Currently I'm mapping the whole file at once (yep!) but of course the...

6. Solaris

restrcit physical memory with zone.max-locked-memory

Is it possible to restrict physical memory in solaris zone with zone.max-locked-memory just like we can do with rcapd ? I do not want to used rcapd

7. Shell Programming and Scripting

How to extract strings from full path when full path is not fixed

/Path/snowbird9/nrfCompMgrRave1230100920.log.gz:09/20/2010 06:14:51 ERROR Error Message. /Path/snowbird6/nrfCompMgrRave1220100920.log.gz:09/20/2010 06:14:51 ERROR Error Message. /Path/snowbird14/nrfCompMgrRave920100920.log.gz:09/20/2010 06:14:51 ERROR Error Message....

8. Solaris

[DOUBT] Memory high in idle process on Solaris 10 (Memory Utilization > 90%)

Hi Experts, Our servers running Solaris 10 with SAP Application. The memory utilization always >90%, but the process on SAP is too less even nothing. Why memory utilization on solaris always looks high? I have statement about memory on solaris, is this true: Memory in solaris is used for...

9. AIX

100% Inode full with only 67% FS full.

AIX Version 6.1 and 7.1. I understand that when the OS initially creates the FS and inodes, its pretty strict, but not always tuned to a 1:1 ratio. I see the same thing when adding a whole disk LV to a separate device. It seems that when we expand a filesystem the inodes don't get tuned...

LEARN ABOUT OSX

dynamic_pager

dynamic_pager(8)					    BSD System Manager's Manual 					  dynamic_pager(8)

NAME

     dynamic_pager -- external storage manager for dynamic pager

SYNOPSIS

     dynamic_pager [-F filename] [-S filesize] [-H high-water-trigger] [-L low-water-trigger] [-P priority]

DESCRIPTION

     The dynamic_pager daemon manages a pool of external swap files which the kernel uses to support demand paging.  This pool is expanded with
     new swap files as load on the system increases.  It is contracted when the swapping resources are no longer needed.  The dynamic_pager daemon
     also provides a notification service for those applications which wish to receive notices when the external paging pool expands or contracts.

OPTIONS

     -F      The base name of the filename to use for the external paging files.  By default this is /private/var/vm/swapfile.

     -H      If there are less than high-water-trigger bytes free in the external paging files, the kernel will signal dynamic_pager to add a new
	     external paging file.

     -L      If there are more than low-water-trigger bytes free in the external paging files, the kernel will coalese in-use pages and signal
	     dynamic_pager to discard an external paging file.	Low-water-trigger must be greater than high-water-trigger + filesize.

     -P      This option is currently unimplemented.

     -S      The fixed filesize [in bytes] to use for the paging files.  By default dynamic_pager uses variable sized paging files, using larger
	     sized files as paging demands increase.  The -S, -H and -L options disable that default and cause dynamic_pager to use a series of
	     fixed sized external paging files.

FILES

     /private/var/vm/swapfile*				 Default external paging files.
     /Library/Preferences/com.apple.virtualMemory.plist  Configuration file.

XML PROPERTY LIST KEYS

     The following keys can be specified in the configuration file.  Please see plist(5) for more information about property list files.

     UseEncryptedSwap <boolean>
     This optional key activates encrypted swap (aka Secure VM), so that all data is encrypted before being written to a swap file.  The default
     is on for portable computers and off for other computers.

Mac OS X							   July 8, 2003 							  Mac OS X