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Memory Utilization At Glance 100%

 
Fuad_1
Regular Advisor

Memory Utilization At Glance 100%

Hi,

How to check the reasones behind the high percentge of memory utilization?
Set goals, and work to achieve them
4 REPLIES 4
Bernhard Mueller
Honored Contributor

Re: Memory Utilization At Glance 100%

Hi,

check the utilization graph, you see system, user and cache in different colors. If the amount of cache is very high you probably have set the kernel parameter dbc_max_pct set to the defautl of 50%.

Probably you have more than 1GB memory and might consider decreasing that parameter to a percentage of Memory that would equal 500-800MB.

check with kmtune -q dbc_max_pct

to change you need to reboot! Can do it using SAM.

also run
# UNIX95= ps -e -o ruser,vsz=Kbytes -o pid,args | sort -n -k 2,2

which will list processes by in-core memory size, largest last; check if there is something suspicious

Regards,
Bernhard
Fuad_1
Regular Advisor

Re: Memory Utilization At Glance 100%

Pysical memory is 4GB, and dbc_max_pct is 10.

What else to check?
Set goals, and work to achieve them
Bernhard Mueller
Honored Contributor

Re: Memory Utilization At Glance 100%

Buffer cache should be OK then.

So you should check if you have many more processes than usually.
If so which ones?
Or did you or somebody else upgrade some software?
Other recent changes?

Regards,
Bernhard
Alexander M. Ermes
Honored Contributor

Re: Memory Utilization At Glance 100%

Hi there.
Check your swap uilization.
If your machine is paging on disks, your performance is down the drain.
You can check it with the key 'm'.
If the system is using disks for swapping
( meaning disk devices shown in next lines ),

/dev/vg00/lvol2 device 1.9gb 0mb 1
/dev/vg09/lvol1 device 2.0gb 0mb 2
/dev/vg16/lvol1 device 16.9gb 0mb 1
pseudo-swap memory 9.3gb 1.7gb na

check the real device usage with looking at the disk devices ( keystroke 'u' ).
If you use Oracle databases, you should test, how much memory you can take off the different databases ( db_block buffers, shared memory area etc ).
Rgds
Alexander M. Ermes
.. and all these memories are going to vanish like tears in the rain! final words from Rutger Hauer in "Blade Runner"