linux memory settings on OL 6.2 ( red hat compatible )

From: John Hurley <>
Date: Thu, 6 Sep 2012 11:06:05 -0700 (PDT)
Message-ID: <>

Our new servers are going thru initial testing now ... moving to 11.2 database and ( at least currently ) OL 6.2 red hat compatible kernel. Was going to try UEK or UEK2 but ... powerpath driver compatibility. Kills me that EMC is not keeping stuff up to date with oracles preferred kernels ... but c'est la vie.

Each of these machines has 96 gb of RAM.

We just finished discovering some issues/bugs with the default setting of anonymous huge pages and set now to never these two: echo never > /sys/kernel/mm/redhat_transparent_hugepage/enabled echo never > /sys/kernel/mm/redhat_transparent_hugepage/defrag

We are using huge pages for Oracle SGA ( so automatic sizing crud turned off ... all manual settings ). Aside from the usual settings for kernel stuff in /etc/sysctl.conf for an oracle database we have ( again ... preliminary testing ) these settings in effect now:


vm.swappiness = 10
vm.vfs_cache_pressure = 200
vm.pagecache = 1 5 10
vm.min_free_kbytes = 81920
vm.nr_hugepages = 28672

EOF To be honest no idea any longer how I came up with the value for min_free_kbytes and for each server ( different purposes ) the hugepages number varies.

Any thing look out of whack or what else should I be thinking about here with the other ones or what am I missing the boat on and should be thinking about?

Thanks in advance! Received on Thu Sep 06 2012 - 13:06:05 CDT

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