Re: [suse-oracle] 10gR2 RAC on SUSE10

Hi Han,

we've got several RACs on 10gR2 and SLES10 x86_64 in production, so neither you nor we are the guinea pigs ;)

Kindly see some comments within your mail body.


> -----Ursprüngliche Nachricht-----
> 1. During the SUSE installation, do I need to tick "High Availability"?
> (I will install Oracle 10.2.0.4 which does not use hangcheck-timer any
> more.)
No.

> 2. Is there any difference to implement HugePages by add hugepages=xx into
> /boot/grub/menu.lst or by adding vm.nr_huge_pages=xx into /etc/sysctl
> please?
I don't know for absolutely sure with grub, but I always set this kind of stuff in /etc/sysctl.conf for higher flexibility (careful changes at run time).

>   I found this subject confusing.  There are many things floating around,
> such as:
>           SHM_USE_BIGPAGES in /etc/sysconfig/oracle,
>           kernel.shm-bigpages-per-file,
>           kernel.shm-use-bigpages,
>           vm.hugetlb_pool,
> 
>   What is SUSE/Oracle's recommendation?  For example, should I set both
> vm.nr_huge_pages and vm.hugetlb_pool?
Settings in /etc/sysconfig/oracle and sysctl.conf end up the same, the oracle start script does the kernel setting same way.

> 3. Do I still need to set Oracle's pre_page_sga=true and lock_sga=true?
> It looks like SUSE 10 fixed vm.disable_cup_mlock issue, but not sure if
> Oracle 10gR2 can see the fix automatically.
NEED is not the topic. pre_page_sga=true means that all SGA will be allocated in one piece, which has advantages and disadvantages. One disadvantage in my experience is, that if the RAC has crashed and has to do instance recovery, the CRS considers the database as dead very easily due to the long startup time. In my special case, I don't use it, but nevertheless I am using hugepages.

lock_sga=true means that the SGA is not to be pages out into swap space. I can only recommend this setting, but remember to set the 
oracle          hard    memlock         -1
oracle          soft    memlock         -1
in /etc/security/limits.conf in order to allow user oracle to pin memory without limit.

> 6. The hardware supports NUMA, but Oracle on X86_64 does not, should NUMA
> be turned on or off please?
There are nice memory fragmentation (or context changing) tests in the net, shame that I can't find the one about NUMA in special at the moment.

Other paper on OS optimization:
http://www.redbooks.ibm.com/redpapers/pdfs/redp3862.pdf
But I guess Arun will explain it all in detail.


> 7. With RAC, the clusterware will startup all services upon reboot, do I
> need to manually disable /etc/init.d/oracle?  Or setting all entries in
> /etc/oratab to 'N' will be enough.
I am using /etc/init.d/oracle and /etc/sysconfig/oracle to set all the kernel parameters like SHMMAX and swith off all other stuff with NO.

Do you know Alejandro Vargas' blog?
http://blogs.oracle.com/AlejandroVargas/

Maybe you want to have a look at my oracle blog as well, there are several RAC topics.
http://www.usn-it.de/index.php/category/it/oracle/



Kind regards,
-- 
Freundliche Grüße

i.A. Martin Klier 
Systemadministration / Datenbanken
        

A.T.U Auto-Teile-Unger 
Handels GmbH & Co. KG 
Dr.-Kilian-Str. 4
92637 Weiden i. d. OPf. 

Tel.: +49 961 306-5663 
Fax:  +49 961 306-5982 

[email protected] 
www.atu.eu
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