RE: How much RAM is to much
Date: Sun, 13 Feb 2011 15:10:01 +0000
Message-ID: <BD475CE0B3EE894DA0CAB36CE2F7DEB4029347_at_LITIGMBCRP02.Corp.Acxiom.net>
I saw that the direct I/O statement got a lot of responses but only 1 on your original question. I'm not sure there's any set number or formula for what is "too big". Starting with around 50% for your SGA isn't a problem and should help out quite a bit. The assumption being that the server is a dedicated database server, with no other major memory consumers. It also assumes that all processes have their PGA factored.
To me, the best thing to do would be run AWR reports and check the SGA target advisory sections. Increase the SGA settings to where you see the biggest gain in performance for the least increase, then monitor for the next few weeks and increase again if necessary. I don't like the idea of relatively blindly increasing a parameter, not knowing if you'll be able to fully utilize the gain. Obviously this approach takes more time but through it I feel you'll understand more about your system's activity.
DAVID HERRING
DBA
Acxiom Corporation
EML dave.herring_at_acxiom.com TEL 630.944.4762 MBL 630.430.5988
1501 Opus Pl, Downers Grove, IL 60515, USA WWW.ACXIOM.COM
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From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Storey, Robert (DCSO)
Sent: Thursday, February 10, 2011 1:03 PM
To: oracle-l-freelists
Subject: How much RAM is to much
So, I'm moving my 9i 32 bit database to a 10g 64 bit database. My 9i box has 4 gig of ram and the usual 23bit limitations. My SGA and such on the 9i box probably hovers around 1.2gig.
I have 24 gig of ram on the new box. From a data aspect, that will darn near load my entire database to memory.
So, in setting SGA_TARGET, how much is too much? Before I was told the box specs, I was thinking 3 gig. But, with 24 gig available, and I'm the ONLY application on the box..how much is to much?
What are the benefits and cons to setting this value at say, 12gig, with a SGA_MAX value of 15G.
-- http://www.freelists.org/webpage/oracle-lReceived on Sun Feb 13 2011 - 09:10:01 CST