High memory utilisation

 
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Vee_1
Frequent Advisor

High memory utilisation

Hello,
I can able to see very high utilization of memory in the below output.Though its having 16GB of physical memory installed ,only 253mb free mem is available .can anybody suggest what could be the issue.

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CPU Util SU | 2% 2% 5%
Disk Util F F | 4% 2% 4%
Mem Util S SU UB B | 98% 98% 98%
Swap Util U UR R | 51% 51% 51%
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MEMORY REPORT Users= 1
Event Current Cumulative Current Rate Cum Rate High Rate
--------------------------------------------------------------------------------
Page Faults 16 75 2.6 10.1 42.1
Page In 13 34 2.1 4.5 15.0
Page Out 0 0 0.0 0.0 0.0
KB Paged In 0kb 0kb 0.0 0.0 0.0
KB Paged Out 0kb 0kb 0.0 0.0 0.0
Reactivations 7 7 1.1 0.9 5.1
Deactivations 24 24 4.0 3.2 4.0
KB Deactivated 0kb 0kb 0.0 0.0 0.0
VM Reads 0 0 0.0 0.0 0.0
VM Writes 0 0 0.0 0.0 0.0

Total VM : 17.3gb Sys Mem : 2.8gb User Mem: 11.7gb Phys Mem: 16.0gb
Active VM: 9.0gb Buf Cache: 1.3gb Free Mem: 253mb

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uptime
1:00pm up 30 days, 4:26, 1 user, load average: 0.04, 0.04, 0.04
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19 REPLIES 19
Kenan Erdey
Honored Contributor

Re: High memory utilisation

Hi,

sys mem seems to be verh high.it can be from memory leak caused by running programs. if it's a database machine you can decrease buffer cache by changing dbc_max_pct kernel parameter. (1.3 gb in your configuration)

Kenan.
Computers have lots of memory but no imagination
Steven E. Protter
Exalted Contributor

Re: High memory utilisation

Shalom,

253 MB is a fairly large chunk of memory to be free.

Perhaps you have an application with a memory leak. Try this script.

http://www.hpux.ws/?p=8

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
TTr
Honored Contributor

Re: High memory utilisation

In your main glance screen, (hit g), look at the RSS column, it provides a good metric of how much memory an application might use. Note I said might because the RSS is the memory that an application has reserved but it may not end up using all of it. The swap utilization looks good at 51%. Hit the w key in glance to see if there is any disk swapping.

Another place to look for memory usage is in shared memory segments, use the command "ipcs -a", it will show you which processes/users are using shared memory.

Controll your kernel buffer cache, search in this forum for dbc_min_pct and dbc_max_pct.
Tim Nelson
Honored Contributor

Re: High memory utilisation

post the output of the following.

ipcs -ma

and

kmtune |grep dbc
or ( 11.11 or 11.23+ )
kctune|grep dbc
Vee_1
Frequent Advisor

Re: High memory utilisation

Thanks Kenan,SEP,TTr& tim.
here is the output and the attachment.

# kmtune |grep dbc
dbc_max_pct 8 - 8
dbc_min_pct 5 - 5
#
Dennis Handly
Acclaimed Contributor

Re: High memory utilisation

>I can able to see very high utilization of memory

This is good, what's the problem?
You aren't doing any Page Outs.
Can you provide "swapinfo -tam".

>here is the output and the attachment.

You ipcs -ma output shows at least two Gb sized segments:
10758 0xac9d4f6c --rw-rw---- oraq44 dba oraq44 dba 53 1201618944
8721 0x00000000 D-rw-rw-rw- q44adm sapsys q44adm sapsys 39 4294967296

Adding these up gives:
Total: 6,818,685,272 count: 48
Tim Nelson
Honored Contributor

Re: High memory utilisation

you still have about 5-6GB unaccounted for. now you will have to look though glance and RSS sizes..

My next guess is that you have a pile of java applications with huge memory allocs. ( just a guess ).

If you have kmeminfo ( can be found by searching this forum ) you can use that with the -user switch to find these mem hogs.


Vee_1
Frequent Advisor

Re: High memory utilisation

Here are the outputs
----------------------------------------------------------------------
Physical memory usage summary (in page/byte/percent):

Physical memory = 4194304 16.0g 100%
Free memory = 43867 171.4m 1%
User processes = 3069096 11.7g 73% details with -user
System = 1070885 4.1g 26%
Kernel = 735341 2.8g 18% kernel text and data
Dynamic Arenas = 445165 1.7g 11% details with -arena
M_TEMP = 355970 1.4g 8%
M_SPINLOCK = 25524 99.7m 1%
M_SWAP = 13360 52.2m 0%
VFD_BT_NODE = 11310 44.2m 0%
KMEM_ALLOC = 4687 18.3m 0%
Other arenas = 34314 134.0m 1% details with -arena
Super page pool = 43985 171.8m 1% details with -kas
Static Tables = 202609 791.4m 5% details with -static
pfdat = 95988 375.0m 2%
htbl2_0 = 32768 128.0m 1%
nbuf = 31728 123.9m 1% bufcache headers
pfn_to_virt = 15998 62.5m 0%
bufhash = 10240 40.0m 0% bufcache hash headers
Other tables = 15886 62.1m 0% details with -static
Buffer cache = 335544 1.3g 8% details with -bufcache
# swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 26272 363 25909 1% 0 - 1 /dev/vg00/pswap
reserve - 16940 -16940
memory 12658 2625 10033 21%
total 38930 19928 19002 51% - 0 -
#
Now the free memory is even more reduced.

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PROCESS LIST Users= 1
User CPU Util Cum Disk Thd
Process Name PID PPID Pri Name ( 600% max) CPU IO Rate RSS Cnt
--------------------------------------------------------------------------------
kernel 12052 12050 154 sdb 4.4/10.5 289398 0.0/ 2.6 6.92gb 225
ps 26621 2016 149 root 0.4/ 0.4 0.0 1.1/ 1.1 56kb 1
midaemon 2322 1 -16 root 0.2/ 0.3 8380.0 0.0/ 0.0 22.1mb 3
java 2016 1 168 root 0.0/ 0.1 2169.5 0.0/ 0.3 35.1mb 18

Don Morris_1
Honored Contributor

Re: High memory utilisation

Of course it is... kmeminfo eats more than a few Mb to run.

I don't see a problem in any of the above -- the system is not paging and likely doesn't consider itself under memory pressure so is willing to let the kernel cache objects/pages for performance. (Just under 1% is the default for vhand to start trying to reduce caches like the Arenas (if free and returnable), the Super Page pool (again if returnable) and the DBC. Note the DBC is still at max... pretty clearly the system is happy with where it is at... only if you push free memory lower will it start to reclaim.)

In short -- the kernel believes it is using your memory effectively for performance and you've shown no indications that it is wrong yet. Idle RAM does you no good, so what is the concern here?