Re: Hugepages usage

Thanks Keith and Andrew.

SQL> sho parameter use_large_p

NAME                                 TYPE                             VALUE
------------------------------------ --------------------------------
------------------------------
use_large_pages                      string                           TRUE
SQL>

NAME                                 TYPE                             VALUE
------------------------------------ --------------------------------
------------------------------
...
memory_max_target                    big integer                      32G
memory_target                        big integer                      32G

SQL>
SQL>
SQL> sho parameter sga

NAME                                 TYPE                             VALUE
------------------------------------ --------------------------------
------------------------------
lock_sga                             boolean                          FALSE
pre_page_sga                         boolean                          TRUE
sga_max_size                         big integer                      30G
sga_target                           big integer                      30G
unified_audit_sga_queue_size         integer

Given that AMM is set, can I assume that ASMM is not enabled and the 'sga' parameters (sga_max_size and sga_target) are for the high values only?

Once the hugepages is enabled at the OS level and if I try to restart with the above AMM settings can I assume the restart will not happen because AMM and huge pages are not compatible?

PS. the server has 64Gb memory.

On Mon, Feb 10, 2020 at 5:24 PM Keith Moore <keithmooredba_at_gmail.com> wrote:

> How large is you SGA? Also, what setting for USE_LARGE_PAGES parameter?
>
> Set USE_LARGE_PAGES to only and see if the database will start. You may
> not have enough huge pages (24 GB).
>
> Keith
>
> On Feb 10, 2020, at 5:20 PM, Ram K <lambu999_at_gmail.com> wrote:
>
>
> Thanks Andrew. What is 'Anonymous Hugepages'. Is it the same as
> Transparent Huge Pages that Oracle recommends to disable
> <https://docs.oracle.com/en/database/oracle/oracle-database/19/unxar/administering-oracle-database-on-linux.html#GUID-02E9147D-D565-4AF8-B12A-8E6E9F74BEEA>
> ?
>
>
> On Mon, Feb 10, 2020 at 5:05 PM Andrew Kerber <andrew.kerber_at_gmail.com>
> wrote:
>
>> You are correct, if the DB is up and running and all the huge pages are
>> free as shown here, they are not being used. Anonymous hugepages should be
>> disabled for all oracle servers.
>>
>> Sent from my iPad
>>
>> > On Feb 10, 2020, at 17:03, Ram K <lambu999_at_gmail.com> wrote:
>> >
>> > 
>> >
>> > Hi,
>> >
>> > I came across this setting in a Linux server running oracle 12.
>> >
>> > grep Huge /proc/meminfo
>> > AnonHugePages: 43008 kB
>> > HugePages_Total: 12288
>> > HugePages_Free: 12288
>> > HugePages_Rsvd: 0
>> > HugePages_Surp: 0
>> > Hugepagesize: 2048 kB
>> >
>> > Does this mean that hugepages are not being used since all the
>> Hugepages are free?
>> > How can I find out if hugepages were ever used, to make sure I am not
>> looking at an isolated time period when it is not being used.
>> >
>> > --
>> > Thanks,
>> > Ram.
>>
>
>
> --
> Thanks,
> Ram.
>
>
>

-- 
Thanks,
Ram.

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