Re: Huge Pages in oracle 11g
Date: Tue, 8 Sep 2015 06:51:22 -0700
Message-ID: <1441720282.86975.YahooMailBasic_at_web184804.mail.gq1.yahoo.com>
> HugePages_Total: 26752
> HugePages_Free: 20097
> HugePages_Rsvd: 11781
> HugePages_Surp: 0
> Hugepagesize: 2048 kB
I would lower HugePages allocation by about 8300 pages (20097-11781=8316 but consider some overhead). Otherwise these pages of 16600 MB will not be used by anybody. The difference between HugePages_Free and HugePages_Rsvd is the wastage, i.e. HugePages that will never be used.
To dynamically deallocate, as root
echo 18452 > /proc/sys/vm/nr_hugepages
cat /proc/sys/vm/nr_hugepages
The number 18452 is 26752-8300. Once that's done, the difference between HugePages_Free and HugePages_Rsvd should be 16. So you're wasting only 32 MB. (Remember to modify /etc/sysctl.conf with the new number.)
See the section "Checking usage" at
http://yong321.freeshell.org/oranotes/HugePages.txt
for a semi-visual explanation of what others in this list have already explained.
-- http://www.freelists.org/webpage/oracle-lReceived on Tue Sep 08 2015 - 15:51:22 CEST