{"id":446,"date":"2008-11-30T21:31:02","date_gmt":"2008-11-30T19:31:02","guid":{"rendered":"http:\/\/www.ora-solutions.net\/web\/?p=446"},"modified":"2008-12-11T11:34:17","modified_gmt":"2008-12-11T09:34:17","slug":"hugepages-revisited","status":"publish","type":"post","link":"https:\/\/www.ora-solutions.net\/web\/2008\/11\/30\/hugepages-revisited\/","title":{"rendered":"Hugepages revisited"},"content":{"rendered":"<p>A while ago<a href=\"http:\/\/www.ora-solutions.net\/web\/2008\/11\/10\/listener-coredumps-on-heavy-load-system\/\"> I wrote a post <\/a>about a specific listener coredump issue which could be solved by 1) installing an oracle patch and 2) by implementing hugepages. I have also linked to an article from Pythian Group Oracle expert <span class=\"author\"><a title=\"Posts by Riyaj Shamsudeen\" href=\"http:\/\/www.pythian.com\/blogs\/author\/shamsudeen\/\">Riyaj Shamsudeen<\/a>, who demonstrated problems with memory page management overheads with big SGAs without hugepages.<\/span><\/p>\n<p>Today, I want to document the steps necessary to implement hugepages after doing some research:<\/p>\n<ul>\n<li>Check your \/etc\/sysctl.conf shmall and shmmax values. I recommend that you set shmmax bigger or<\/li>\n<li>Check your current total shared memory segment size. Depending on your &#8220;bc -l&#8221; skills by summing all byte lines from ipcs -m or by executing a script from metalink Note <small>401749.1 <\/small>(which does exactly that). Calculate how many hugepages you need by &#8220;cat \/proc\/meminfo&#8221; and dividing it by the pagesize of your platform. (Linux IA64 has 256MB pages for example) I recommend to add 1 extra page for safety.<\/li>\n<li>Say, you need 200 hugepages. Multiply it with the pagesize and enter this value in<br \/>\n<strong>\/etc\/security\/limits.conf<\/strong>: (values in kb)<\/li>\n<\/ul>\n<blockquote><p>oracle soft memlock 2097152<br \/>\noracle hard memlock 2097152<\/p><\/blockquote>\n<ul>\n<li>Set the parameters in <strong>\/etc\/sysctl.conf<\/strong>:<\/li>\n<\/ul>\n<blockquote><p>vm.nr_hugepages=200<br \/>\nvm.hugetlb_shm_group=&lt;group id of dba group from \/etc\/group&gt;<br \/>\ne.g. vm.hugetlb_shm_group=201<\/p><\/blockquote>\n<p>I am going to implement hugepages on Linux Itanium for a Real Application Cluster system. I have read posts that there are different issues regarding startup with srvctl or sqlplus and startup by oracle or root. I will investigate and write more soon.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A while ago I wrote a post about a specific listener coredump issue which could be solved by 1) installing an oracle patch and 2) by implementing hugepages. I have also linked to an article from Pythian Group Oracle expert Riyaj Shamsudeen, who demonstrated problems with memory page management overheads with big SGAs without hugepages. [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[44,5,12],"tags":[],"class_list":["post-446","post","type-post","status-publish","format-standard","hentry","category-linux-unix-2","category-oracle-database","category-unix"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ora-solutions.net\/web\/wp-json\/wp\/v2\/posts\/446","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ora-solutions.net\/web\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ora-solutions.net\/web\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ora-solutions.net\/web\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ora-solutions.net\/web\/wp-json\/wp\/v2\/comments?post=446"}],"version-history":[{"count":6,"href":"https:\/\/www.ora-solutions.net\/web\/wp-json\/wp\/v2\/posts\/446\/revisions"}],"predecessor-version":[{"id":493,"href":"https:\/\/www.ora-solutions.net\/web\/wp-json\/wp\/v2\/posts\/446\/revisions\/493"}],"wp:attachment":[{"href":"https:\/\/www.ora-solutions.net\/web\/wp-json\/wp\/v2\/media?parent=446"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ora-solutions.net\/web\/wp-json\/wp\/v2\/categories?post=446"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ora-solutions.net\/web\/wp-json\/wp\/v2\/tags?post=446"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}