Re: Hugepages question with multiple instances on 1 host
From: Nuno Souto <dbvision_at_iinet.net.au>
Date: Tue, 30 Apr 2013 15:27:52 +1000
Message-ID: <517F5658.7_at_iinet.net.au>
Careful as well with the differences between Linux and Unix. Before 11r2, you can use LOCK_SGA=true to make an instance use largepages/hugepages if they are configured. Set it fo false and it won't use them. That's in Un*x. Not sure what the situation is with Linux.
IIRC, the term "largepages is used in Un*x and "hugepages" is the terminology used in Linux. Bottom line: they are one and the same, it's just that the Linux folks like to make themselves sound bigger... As well, the parameter Alex mentioned might be undocumented. It certainly is not in the 11gr2 doco.
Date: Tue, 30 Apr 2013 15:27:52 +1000
Message-ID: <517F5658.7_at_iinet.net.au>
Careful as well with the differences between Linux and Unix. Before 11r2, you can use LOCK_SGA=true to make an instance use largepages/hugepages if they are configured. Set it fo false and it won't use them. That's in Un*x. Not sure what the situation is with Linux.
IIRC, the term "largepages is used in Un*x and "hugepages" is the terminology used in Linux. Bottom line: they are one and the same, it's just that the Linux folks like to make themselves sound bigger... As well, the parameter Alex mentioned might be undocumented. It certainly is not in the 11gr2 doco.
-- Cheers Nuno Souto dbvision_at_iinet.net.au On 30/04/2013 12:29 AM, Alex Fatkulin wrote:Received on Tue Apr 30 2013 - 07:27:52 CEST
> You sure can,
> if you're on 11.2 then you can specify use_large_pages=only for DB1 and
> use_large_pages=false on DB2.
>
> On previous version it'll be a little bit trickier -- probably the easiest
> way is to start DB1 _before_ you start DB2 so DB1 can claim all the huge
> pages leaving DB2 with only regular pages to allocate. That is unless you
> want to setup two different users and do it via OS limits.
>
>
> On Mon, Apr 29, 2013 at 10:19 AM, <Christopher.Taylor2_at_parallon.net> wrote:
>
>> I think this is a quick question.
>> As I'm going through the hugepages information, I'm trying to figure out
>> if you can, or cannot, have multiple instances on 1 host running different
>> configurations?
>>
>> Such as
>> DB_1 running hugepages (32GB SGA)
>> DB_2 running regular pages (4GB SGA)
>>
>> It seems that all instances will need to be in hugepages?
>>
>> Thanks
>>
>> Chris Taylor
>> Oracle DBA
>> Parallon IT&S
>>
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