high memory usage on Linux host

high memory usage on Linux host

am 08.11.2010 10:33:53 von askzaman askzaman

In one of Linux host , sar is showing always high memory usage .
looks like some little amount of swapping also ( %swpused ) but free
is not reporting any swapping.

=====
12:00:01 AM kbmemfree kbmemused %memused kbbuffers kbcached
kbswpfree kbswpused %swpused kbswpcad

08:40:01 AM 224796 7944056 97.25 178364
5898568 8121928 432 0.01 432
08:50:01 AM 224724 7944128 97.25 178364
5898500 8121928 432 0.01 432
09:00:01 AM 224572 7944280 97.25 178364
5898500 8121928 432 0.01 432
Average: 227441 7941411 97.22 178339
5898181 8121928 432 0.01 432
------
-bash-3.00$ free -m
total used free shared buffers cached
Mem: 7977 7752 224 0 174 5760
-/+ buffers/cache: 1818 6159
Swap: 7931 0 7931
=====


The host has apache , java running and one our custom application .
But these applications are just running and are not serving any
traffic .

====
Tasks: 221 total, 1 running, 220 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.2% us, 0.1% sy, 0.0% ni, 99.2% id, 0.0% wa, 0.0% hi, 0.5% si
Mem: 8168852k total, 7942712k used, 226140k free, 178372k buffers
Swap: 8122360k total, 432k used, 8121928k free, 5898628k cached

PID USER PR NI %CPU TIME+ %MEM VIRT RES SHR S COMMAND
19657 nobody 16 0 0 1:30.18 1.5 719m 122m 9.9m S
java_daemon
6545 nobody 15 0 1 198:18.07 1.0 527m 83m 5508 S
tcs_server
15732 nobody 16 0 0 2:23.94 0.2 31964 18m 5008 S apache
15716 nobody 16 0 0 2:08.11 0.2 32016 18m 4952 S apache
15733 nobody 16 0 0 2:09.58 0.2 31980 18m 4944 S apache
15718 nobody 16 0 0 2:27.99 0.2 31976 18m 4936 S apache
15735 nobody 16 0 0 2:28.53 0.2 31952 18m 4952 S apache
15738 nobody 16 0 0 2:39.02 0.2 31952 18m 4928 S apache
15727 nobody 16 0 0 2:16.02 0.2 31948 18m 4920 S apache
15725 nobody 16 0 0 2:28.89 0.2 32024 18m 4928 S apache
15724 nobody 16 0 0 2:25.61 0.2 31856 18m 4944 S apache
7076 nobody 16 0 0 2:01.68 0.2 31400 18m 4912 S
apache
7091 nobody 16 0 0 2:03.89 0.2 31316 17m 4936 S
apache
====


The above out is in terms of high memory usage.

Can somebody explain why sar is reporting high memory usage on host .


The OS is RHEL 4 .


Any help will be highly appreciated.
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Re: high memory usage on Linux host

am 08.11.2010 10:43:55 von Liganic

> The host has apache , java running and one our custom application .
> But these applications are just running and are not serving any
> traffic .
Have you looked into your -Xms or similar options for Java? If you are
giving it a high initial value, it will not drop below that. Also what
do you perceive as high memory usage? 77% of your memory are free
(subtracting the caches).

Regards,
--
Michael Wünsch
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Re: high memory usage on Linux host

am 08.11.2010 11:25:37 von nmaupu

Hi,

I presume SAR does not substract buffers and caches memory to compute
percentage ...

Regards,
Nicolas Maupu

On Mon, Nov 8, 2010 at 10:43, Michael Wünsch wrote:
>
> > The host has apache , java =A0running and one our custom applicatio=
n .
> > But these applications are just running =A0and are not serving any
> > traffic .
> Have you looked into your -Xms or similar options for Java? If you ar=
e
> giving it a high initial value, it will not drop below that. Also wha=
t
> do you perceive as high memory usage? 77% of your memory are free
> (subtracting the caches).
>
> Regards,
> --
> Michael Wünsch
> --
> To unsubscribe from this list: send the line "unsubscribe linux-admin=
" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at =A0http://vger.kernel.org/majordomo-info.html



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