Re: RHEL memory questions

From: David Ramírez Reyes <dramirezr_at_gmail.com>
Date: Fri, 2 Oct 2015 17:45:16 -0500
Message-ID: <CAJt=wvXypb0=Wz78=rntxsvWKyG04Gb4HuqmjYcpqZQ0QJN=KA_at_mail.gmail.com>

Thanks guys for the answer, this helped me to understand the memory usage on Linux.

Regards

On Friday, 2 October 2015, Mark Brinsmead <mark.brinsmead_at_gmail.com> wrote:

> On most Linux (Unix) systems, it is completely normal to see memory is
> roughly 100% utilized, unless the system is sitting idle.
>
> Any memory not used by your applications is usually taken by the operating
> system for filesystem buffers.
>
> Seeing memory at or near 100% (total) utilization is not necessarily an
> indication of a problem. Nor is it necessarily an indication that the
> memory is being used effectively. (On an Oracle database server, memory is
> usually put to better use in your SGA and PGA than in filesystem buffers.)
>
> There are others here who can -- I am sure -- answer much more precisely
> than I have, so I'll go back to lurking now.
>
> Cheers!
>
> On Wed, Sep 30, 2015 at 5:53 PM, David Ramírez Reyes <dramirezr_at_gmail.com
> <javascript:_e(%7B%7D,'cvml','dramirezr_at_gmail.com');>> wrote:
>
>> Hello List!
>>
>>
>>
>> Am just starting working with Oracle (11g R2) over RHEL(5) and I have
>> some basic doubts that I would like to clarify (until now, I’ve been
>> working with Oracle over Windows):
>>
>>
>>
>> - As part of a daily DB report, I need to check the memory
>> usage of the server and am getting these:
>>
>> total used free shared buffers cached
>>
>> Mem: 62 61 1 0 1 55
>>
>> -/+ buffers/cache: 4 58
>>
>> Swap: 31 0 31
>>
>> Total: 94 61 33
>>
>>
>>
>> As you can see, “free” memory is almost over (although there’s no swap)
>> which makes me report that memory usage is at 98% (it sounds strange to
>> me), is this a normal behavior?; I’ve checked the processes running and
>> there’s no a pick process but many opened by the oracle connections to the
>> DB; depending on the answer, the next questions would be if more memory is
>> required or if there’s a way to limit the memory that Oracle uses (on
>> Windows, there’s a single Oracle process –with all subprocesses inside- and
>> is very easy to determine and restrict the memory used by the DB, here in
>> Linux seems like I need to sum the memory used by all processes for oracle
>> user and seems not easy to restrict to a limit, is this correct?).
>>
>>
>>
>> Any advice, tip or trick for an Oracle DBA over Linux is well received.
>>
>>
>>
>> Thanks
>>
>>
>> David Ramírez Reyes
>> Profesión: Padre de Familia
>>
>>
>>
>>
>>
>

-- 
David Ramírez Reyes
Profesión: Padre de Familia

--
http://www.freelists.org/webpage/oracle-l

Received on Sat Oct 03 2015 - 00:45:16 CEST