Re: Configuring HUGE PAGES

From: Mark Bobak <Mark.Bobak_at_proquest.com>
Date: Wed, 20 Nov 2013 20:28:29 +0000
Message-ID: <CEB284DC.3B4CB%Mark.Bobak_at_ProQuest.com>

You should specifically set hugepages to the size of your SGA. You should not set it to all available memory, or your server likely not boot. Memory reserved for use by hugepages, *cannot* be used by the system for anything else. Memory allocated as hugepages, *must* be allocated and used as hugepages.

Also, this is not to be confused with transparent hugepages, which is bad, and should be disabled. See MOS Doc ID 1557478.1 for details on that.

Hope that helps,

-Mark

From: "JBECKSTROM_at_gcrta.org<mailto:JBECKSTROM_at_gcrta.org>" <JBECKSTROM_at_gcrta.org<mailto:JBECKSTROM_at_gcrta.org>> Reply-To: "JBECKSTROM_at_gcrta.org<mailto:JBECKSTROM_at_gcrta.org>" <JBECKSTROM_at_gcrta.org<mailto:JBECKSTROM_at_gcrta.org>> Date: Wednesday, November 20, 2013 at 3:22 PM To: Don Seiler <don_at_seiler.us<mailto:don_at_seiler.us>> Cc: oracle-l-freelists <oracle-l_at_freelists.org<mailto:oracle-l_at_freelists.org>>, oracle-db-l <oracle-db-l_at_Groups.ITtoolbox.com<mailto:oracle-db-l_at_Groups.ITtoolbox.com>> Subject: Re: Configuring HUGE PAGES

Can you configure HUGE Pages to use all available memory? Would the PGA then just ignore the setting and use normal pages instead. Do you have to specifically allocate only enough memory for HUGE Pages to cover the SGA and leaving the rest as normal?

Jeffrey Beckstrom
Database Administrator
Greater Cleveland Regional Transit Authority Information Systems
1240 W. 6th Street
Cleveland, Ohio 44113
>>> Don Seiler <don_at_seiler.us<mailto:don_at_seiler.us>> 11/20/13 3:19 PM >>>
The PGA can't go into HugePages, only SGA. So you only need to worry about the SGA pools and buffer cache. For this same reason, you can't use AMM if you want to use HugePages, you have to set memory_target and memory_max_size to 0.

On Wed, Nov 20, 2013 at 2:13 PM, Jeffrey Beckstrom <JBECKSTROM_at_gcrta.org<mailto:JBECKSTROM_at_gcrta.org>> wrote: We are looking at migrating to Linux. We would like to configure HUGE Pages. When determining how many HUGE PAGES to allocate, do we just consider the SGA, the SGA and PGA or should all memory be assigned to HUGE Pages. Jeffrey Beckstrom
Database Administrator
Greater Cleveland Regional Transit Authority Information Systems
1240 W. 6th Street
Cleveland, Ohio 44113

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Received on Wed Nov 20 2013 - 21:28:29 CET