RE: How do you calculate Large Page settings for Oracle on AIX?

  • From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
  • To: "kamusis@xxxxxxxxx" <kamusis@xxxxxxxxx>, oracle_l <Oracle-L@xxxxxxxxxxxxx>
  • Date: Thu, 6 Jan 2011 10:47:07 -0700

I'm not sure what the problems is - maybe you have another Oracle instance or 
something else also using large pages?  You can use svmon to get more detail 
about what is using the large pages but I would recommend just not using large 
pages anymore.  With Oracle 10.2.0.4+ you can use the newer and 
easier-to-manage "medium" (64K) pages as instructed and recommended by IBM here 
(and also mentioned in MOS Doc ID 968113.1):

http://public.dhe.ibm.com/partnerworld/pub/whitepaper/162b6.pdf

"The new 64 KB pages are preferred over 16 MB pages, and it is recommended that 
you use them instead of 16 MB pages on systems that support both page sizes. 
This is because 64 KB pages provide most of the benefit of 16 MB pages, without 
the special tuning requirements of 16 MB pages. If the memory is not properly 
tuned for 16 MB pages, the performance can be worse."

Just beware of the bug described in MOS Doc ID 1088076.1

I used to use large pages (only or the SGA, not for .text and .data) and they 
worked fine for years, but I've been using the newer medium pages for the last 
year or so and haven't had any problems.

Regards,
Brandon


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