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Old 05-03-2012, 08:42 PM
Lucio M Nicolosi
 
Default Oracle Coherence increasing Swap Utilization

On Thu, May 3, 2012 at 3:30 PM, Akash Jain <akash.delhite@gmail.com> wrote:
> We are using Oracle Coherence on linux servers. However, we noticed that
> because of Coherence processes running, often our swap utilization %
> increases too much, sometimes becoming more than 98%, even touched 100% a
> few times.
>
> Once we kill all the coherence related processes, then it becomes normal.
>
> Is there any way we can make coherence processes to only use a particular
> size of Swap space ?
>
> Currently increasing swap space is not in our scope.

Perhaps you should increase your RAM size AND cache size and check
Oracle Documents:

From:

http://docs.oracle.com/cd/E24290_01/coh.371/e22838/tune_perftune.htm

"6.1.5 Swapping

Swapping, also known as paging, is the use of secondary storage to
store and retrieve application data for use in RAM memory. Swapping is
automatically performed by the operating system and typically occurs
when the available RAM memory is depleted. Swapping can have a
significant impact on Coherence's performance and should be avoided.
Often, swapping manifests itself as Coherence nodes being removed from
the cluster due to long periods of unresponsiveness caused by them
having been swapped out of RAM. See "Avoid using virtual memory
(paging to disk)." for more information.

To avoid swapping, ensure that sufficient RAM memory is available on
the computer or that the number of running processes is accounted for
and do not consume all the available RAM. Tools such as vmstat and top
(on Unix and Linux) and taskmgr (on Windows) should be used to monitor
swap rates.

Swappiness in Linux

Linux, by default, may choose to swap out a process or some of its
heap due to low usage even if it is not running low on RAM. Swappiness
is performed to be ready to handle eventual memory requests.
Swappiness should be avoided for Coherence JVMs. The swappiness
setting on Linux is a value between 0 and 100, where higher values
encourage more optimistic swapping. The default value is 60. For
Coherence, a lower value (0 if possible) should always be set.

To see the current swappiness value that is set, enter the following
at the command prompt:

cat /proc/sys/vm/swappiness

To temporarily set the swappiness, as the root user echo a value onto
/proc/sys/vm/swappiness. The following example sets the value to 0.

echo 0 > /proc/sys/vm/swappiness

To set the value permanently, modify the /etc/sysctl.conf file."

L.

--
Lucio M. Nicolosi, Eng.
Open Source Implementation
System and Applications
GNU/Linux

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Old 05-03-2012, 08:52 PM
Lucio M Nicolosi
 
Default Oracle Coherence increasing Swap Utilization

On Thu, May 3, 2012 at 5:42 PM, Lucio M Nicolosi <lmnicolosi@gmail.com> wrote:
> On Thu, May 3, 2012 at 3:30 PM, Akash Jain <akash.delhite@gmail.com> wrote:

>>
>> Currently increasing swap space is not in our scope.
>
> Perhaps you should increase your RAM size AND cache size and check
> Oracle Documents:
>

Where I wrote "cache" please understand "swap".

L.

--
Lucio M. Nicolosi, Eng.
Open Source Implementation
System and Applications
GNU/Linux

--
ubuntu-users mailing list
ubuntu-users@lists.ubuntu.com
Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-users
 

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