RE: Large SGA in Solaris

From: Tanel Poder <>
Date: Fri, 8 May 2009 15:44:00 +0300
Message-ID: <41DE6ACE4DDE436A9D31BCAE98F84932_at_porgand>

That's what I said in my post too ;-)  

When you use DISM it means you are using pageable memory for SGA. Non-dynamic ISM will use non-pageable memory pages, which are locked into physical RAM. When a page is not pageable, it can't be paged out, thus it doesn't need swap space to back that allocation.  

And yes, I do have a blog entry describing this ;-) memory/

Tanel Poder <>

From: [] On Behalf Of Charles Schultz
Sent: 08 May 2009 15:16
Cc: oracle-l-freelists
Subject: Re: Large SGA in Solaris

Just to add to that, the swap space for DISM has to be backed by disk. We found this through trial and testing. =) Just throwing up some ramfs is not good enough. I am not exactly sure why this is, as I have not yet fully understood the whitepapers that Sun and Oracle both provided.

On Fri, May 8, 2009 at 06:37, Tanel Poder <> wrote:

Oracle uses large pages (ISM) by default on solaris, so you'll get 4MB or larger pages on SPARC. ISM/DISM pagetables are sharable so you shouldn't have any kernel memory overhead problems.  

-- Received on Fri May 08 2009 - 07:44:00 CDT

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