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Full Discussion: Memory usage in AIX server
Operating Systems AIX Memory usage in AIX server Post 302843466 by rbatte1 on Tuesday 13th of August 2013 11:54:35 AM
Old 08-13-2013
Don't panic!

AIX is very good at keeping memory full with all sorts of things it believes will be useful. If something is not needed now, there is no reason to actually scrub memory unless another process is allocated that address to work in. I used to worry about this too. It can (as you suggest) be used for all sorts of caching. It is faster than reading from the disk, but there is no point in paging it out, so it just gets lost if not used. When a process then needs the data, it is just read from disk as normal, which is no different than paging back in (unless you have wildly different performance disks) but to use the paging, it would have to keep a record that it existed etc., so it's more effort to page this kind of thing.


Basically, if the server is not paging, then it is fine. Smilie


There used to be a rule of thumb for double paging space for your RAM. Then that changed (even less formally if that's possible) to double RAM for the first 2Gb, then 1Gb for the rest of your RAM allocation.

Of course, what you really need to estimate is the total space you will need and balance the cost against the speed of real memory. Beyond what you can justify paying for, allocate paging to cover it, and a bit more to be sure. Very inexact though. Have some sort of monitor that check paging space, either have a regular look with lsps -a or vmstat, sar or other tools just to keep a check on how much you are really using.

If you are paranoid about crashing the server, allocate lots extra paging space, but don't try to grow /dev/hd6. If you succeed, you will never be able extract it without considerable effort. Smilie

If you allocate 2Gb chunks as paging00, paging01, paging02 ....etc., then when your service is settled, you can work out how many to remove.

If you can space a disk, create a dedicated VG for them in the short term, rather than filling up rootvg and making DR recovery a problem.



I hope that this helps,

Robin
Liverpool/Blackburn
UK
 

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Info::CiscoStats(3pm)					User Contributed Perl Documentation				     Info::CiscoStats(3pm)

NAME
SNMP::Info::CiscoStats - Perl5 Interface to CPU and Memory stats for Cisco Devices AUTHOR
Eric Miller, Max Baker, Sam Stickland SYNOPSIS
# Let SNMP::Info determine the correct subclass for you. my $ciscostats = new SNMP::Info( AutoSpecify => 1, Debug => 1, # These arguments are passed directly on to SNMP::Session DestHost => 'myswitch', Community => 'public', Version => 2 ) or die "Can't connect to DestHost. "; my $class = $ciscostats->class(); print "SNMP::Info determined this device to fall under subclass : $class "; DESCRIPTION
SNMP::Info::CiscoStats is a subclass of SNMP::Info that provides cpu, memory, os and version information about Cisco Devices. Use or create in a subclass of SNMP::Info. Do not use directly. Inherited Classes None. Required MIBs CISCO-PRODUCTS-MIB CISCO-PROCESS-MIB CISCO-MEMORY-POOL-MIB SNMPv2-MIB OLD-CISCO-SYSTEM-MIB CISCO-STACK-MIB CISCO-ENTITY-VENDORTYPE-OID-MIB CISCO-FLASH-MIB ENTITY-MIB MIBs can be found at ftp://ftp.cisco.com/pub/mibs/v2/v2.tar.gz GLOBALS
$ciscostats->cpu() Returns ios_cpu() or cat_cpu(), whichever is available. $ciscostats->cpu_1min() Returns ios_cpu_1min() or cat_cpu1min(), whichever is available. $ciscostats->cpu_5min() Returns ios_cpu_5min() or cat_cpu5min(), whichever is available. $ciscostats->mem_total() Returns mem_free() + mem_used() $ciscostats->vendor() 'cisco' $ciscostats->os() Tries to parse if device is running IOS or CatOS from description() Available values : pix Cisco PIX asa Cisco ASA fwsm Single-mode FWSM fwsm-admin Admin context of multi-context FWSM fwsm-context Standard context of multi-context FWSM ace-admin Admin context of ACE module ace-context Standard context of ACE module (NB: No OS version detection is available, but will be the same as it's 'ace admin') css Cisco Content Switch css-sca Cisco Content Switch Secure Content Acceleration $ciscostats->os_ver() Tries to parse device operating system version from description() $ciscostats->os_bin() Tries to parse ROMMON version from rom_id() string $ciscostats->ios_cpu() Current CPU usage in percent. 1.3.6.1.4.1.9.2.1.56.0 = "OLD-CISCO-CPU-MIB:avgBusyPer" $ciscostats->ios_cpu_1min() Average CPU Usage in percent over the last minute. 1.3.6.1.4.1.9.2.1.57.0 $ciscostats->ios_cpu_5min() Average CPU Usage in percent over the last 5 minutes. 1.3.6.1.4.1.9.2.1.58.0 $ciscostats->cat_cpu() Current CPU usage in percent. "CISCO-PROCESS-MIB::cpmCPUTotal5sec.9" $ciscostats->cat_cpu_1min() Average CPU Usage in percent over the last minute. "CISCO-PROCESS-MIB::cpmCPUTotal1min.9" $ciscostats->cat_cpu_5min() Average CPU Usage in percent over the last 5 minutes. "CISCO-PROCESS-MIB::cpmCPUTotal5min.9" $ciscostats->mem_free() Main DRAM free of the device in bytes. "CISCO-MEMORY-POOL-MIB::ciscoMemoryPoolFree" $ciscostats->mem_used() Main DRAM used of the device in bytes. "CISCO-MEMORY-POOL-MIB::ciscoMemoryPoolUsed" $ciscostats->mem_total() Main DRAM of the device in bytes. "CISCO-MEMORY-POOL-MIB::ciscoMemoryPoolFree" + "CISCO-MEMORY-POOL-MIB::ciscoMemoryPoolUsed" $ciscostats->flashmem_total() Flash memory of the device in bytes. "CISCO-FLASH-MIB::ciscoFlashDeviceSize" TABLE METHODS
Cisco Memory Pool Table ("ciscoMemoryPoolTable") $ciscostats->cisco_mem_free() The number of bytes from the memory pool that are currently unused on the managed device. ("ciscoMemoryPoolFree") $ciscostats->cisco_mem_used() The number of bytes from the memory pool that are currently in use by applications on the managed device. ("ciscoMemoryPoolUsed") Cisco Flash Device Table ("ciscoFlashDeviceTable") $ciscostats->cisco_flash_size() Total size of the Flash device. For a removable device, the size will be zero if the device has been removed. ("ciscoFlashDeviceSize") perl v5.12.4 2011-09-28 Info::CiscoStats(3pm)
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