{"id":1185,"date":"2026-10-15T10:33:52","date_gmt":"2026-10-15T08:33:52","guid":{"rendered":"https:\/\/anjo.pt\/keyword-oracle\/?p=1185"},"modified":"2026-10-15T10:39:26","modified_gmt":"2026-10-15T08:39:26","slug":"solve-ora-27106-when-starting-db-without-restart-the-system","status":"publish","type":"post","link":"https:\/\/anjo.pt\/keyword-oracle\/2026\/10\/15\/solve-ora-27106-when-starting-db-without-restart-the-system\/","title":{"rendered":"Solve ORA-27106 when starting DB without restart the system"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">On Oracle 19c and above, my recommendation is to have the parameter USE_LARGE_PAGES=AUTO_ONLY.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This means that the database will allocate huge pages automatically and only start if it was successful doing so. No need to configure manually \/etc\/sysctl.conf (the nr_hugepages) anymore.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">On a server today, when starting the database I got this:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\noracle@myclient $ srvctl start database -db CLIENTDB_SITE1\nPRCR-1079 : Failed to start resource ora.clientdb_site1.db\nCRS-5017: The resource action &quot;ora.clientdb_site1.db start&quot; encountered the following error:\nORA-27106: system pages not available to allocate memory\nAdditional information: 6212\nAdditional information: 1\n. For details refer to &quot;(:CLSN00107:)&quot; in &quot;\/u00\/app\/oracle\/diag\/crs\/myclient\/crs\/trace\/ohasd_oraagent_oracle.trc&quot;.\n\nCRS-2674: Start of &#039;ora.clientdb_site1.db&#039; on &#039;myclient&#039; failed\n<\/pre><\/div>\n\n\n<p class=\"wp-block-paragraph\">The database is configured with SGA_TARGET=20G (SGA_MAX_TARGET is not set) and there is enough memory in the server:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\noracle@myclient $ free -h\n              total        used        free      shared  buff\/cache   available\nMem:          125Gi        62Gi        27Gi        21Gi        36Gi        41Gi\nSwap:         4.0Gi          0B       4.0Gi\n<\/pre><\/div>\n\n\n<p class=\"wp-block-paragraph\">We see there are 41G available. Problem is that hugepages require a continuous blocks and the buffer\/cache slots were fragmenting the memory.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Luckily it was enough to clear the part of the PageCache (this is a safe operation, there were other DBs running on the server):<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\noracle@myclient $ sudo sync  # make sure all is written to disk\noracle@myclient $ sudo echo 1 | sudo tee \/proc\/sys\/vm\/drop_caches  # clear PageCache\n\noracle@myclient $ free -h\n              total        used        free      shared  buff\/cache   available\nMem:          125Gi        58Gi        44Gi        20Gi        22Gi        46Gi\nSwap:         4.0Gi       0.0Ki       4.0Gi\n<\/pre><\/div>\n\n\n<p class=\"wp-block-paragraph\">We see it released 14GB of memory, and then it had enough continuous blocks to provide 20G of huge pages and the database could be started.<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\noracle@myclient $ srvctl start database -db CLIENTDB_SITE1\n\noracle@myclient $ free -h\n              total        used        free      shared  buff\/cache   available\nMem:          125Gi        75Gi        26Gi        20Gi        23Gi        28Gi\nSwap:         4.0Gi       0.0Ki       4.0Gi\n<\/pre><\/div>\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>On Oracle 19c and above, my recommendation is to have the parameter USE_LARGE_PAGES=AUTO_ONLY. This means that the database will allocate huge pages automatically and only start if it was successful doing so. No need to configure manually \/etc\/sysctl.conf (the nr_hugepages) anymore. On a server today, when starting the database I got this: The database is [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35,6],"tags":[],"class_list":["post-1185","post","type-post","status-publish","format-standard","category-linux","category-oracle","czr-hentry"],"_links":{"self":[{"href":"https:\/\/anjo.pt\/keyword-oracle\/wp-json\/wp\/v2\/posts\/1185","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/anjo.pt\/keyword-oracle\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/anjo.pt\/keyword-oracle\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/anjo.pt\/keyword-oracle\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/anjo.pt\/keyword-oracle\/wp-json\/wp\/v2\/comments?post=1185"}],"version-history":[{"count":3,"href":"https:\/\/anjo.pt\/keyword-oracle\/wp-json\/wp\/v2\/posts\/1185\/revisions"}],"predecessor-version":[{"id":1189,"href":"https:\/\/anjo.pt\/keyword-oracle\/wp-json\/wp\/v2\/posts\/1185\/revisions\/1189"}],"wp:attachment":[{"href":"https:\/\/anjo.pt\/keyword-oracle\/wp-json\/wp\/v2\/media?parent=1185"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/anjo.pt\/keyword-oracle\/wp-json\/wp\/v2\/categories?post=1185"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/anjo.pt\/keyword-oracle\/wp-json\/wp\/v2\/tags?post=1185"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}