{"id":7894,"date":"2019-06-09T11:55:49","date_gmt":"2019-06-09T11:55:49","guid":{"rendered":"https:\/\/rax-stg-wp-aws.com\/blogs\/exploring-flex-asm-and-other-oracle-features\/"},"modified":"2026-11-03T19:29:08","modified_gmt":"2026-11-03T19:29:08","slug":"exploring-flex-asm-and-other-oracle-features","status":"publish","type":"blogs","link":"https:\/\/www.rackspace.com\/en-gb\/blogs\/exploring-flex-asm-and-other-oracle-features\/","title":{"rendered":"Exploring Flex ASM and other Oracle features"},"content":{"rendered":"<p><strong>Introduction<\/strong><\/p>\n<p>Oracle\u00a9 version 12.1.0.1 has incorporated two new features based on Hub and Leaf node architecture.<\/p>\n<p>The new features are:<\/p>\n<ul>\n<li>Flex Cluster<\/li>\n<li>&nbsp;Flex Automatic Storage Management (Flex ASM)<\/li>\n<\/ul>\n<p>Oracle implements the Flex ASM feature by default in Oracle Database Appliance&nbsp;(ODA) version 12.1.x, along with the ASM Dynamic Volume Manager (ADVM) Proxy&nbsp;instance and the Grid Infrastructure Management Repository database, <em>MGMTDB<\/em>.<br \/>\nThis blog explains Flex ASM, ADVM and MGMTDB features and the associated&nbsp;benefits.&nbsp;<\/p>\n<p><strong>Flex ASM<\/strong><\/p>\n<p>Flex ASM reduces the ASM instance footprint by running on each node of the&nbsp;cluster, and also ensures that the database instance has high availability, in&nbsp;case of ASM instance failure on a particular node. You can configure Flex ASM&nbsp;by using dedicated ASM network, or you can share the private interconnect used&nbsp;by the cluster. The following images show the test cases performed for Flex ASM:<\/p>\n<p><em>Cluster ASM listener Node1:<\/em><\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture1_37.png\" alt=\"flex asm pic 1\" \/><\/p>\n<p><em>Cluster ASM listener Node2:&nbsp;<\/em><\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture2_24.png\" alt=\"Flex asm part 2\" \/><\/p>\n<p>Use the following code to check the ASM cluster mode and state:<\/p>\n<p>&nbsp;<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture3_19.png\" alt=\"asm pic 3\" \/><\/p>\n<p>Use the following code to check ASM status:<\/p>\n<p>&nbsp;<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture4_14.png\" alt=\"flex asm pic 4\" \/><\/p>\n<p>Use the following code to check ASM configuration:<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture5_12.png\" alt=\"asm flex pic 5\" \/><\/p>\n<p><strong>NOTE<\/strong>: You can reduce an ASM instance count to a minimum of two by using the&nbsp;following command, which shows instances running on Node1<\/p>\n<p><em>&nbsp; srvctl modify asm -count 2<\/em><\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture6_10.png\" alt=\"asm flex pic 6\" \/><\/p>\n<p>Then run the following code:<\/p>\n<p>&nbsp; &nbsp; <em>srvctl status asm -node ushodld0001ca<\/em><\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture7_7.png\" alt=\"flex asm pic 7\" \/><\/p>\n<p>&nbsp;Then run the following code:<\/p>\n<p><em>&nbsp; &nbsp; srvctl status asm -node ushodld0001ca<\/em><\/p>\n<p>&nbsp;Now, you need to stop the ASM instance on Node1 by running the following command:<\/p>\n<p><em>&nbsp; &nbsp; srvctl stop asm -node ushodld0001ca -stopoption abort \u2013force<\/em><\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture8_6.png\" alt=\"flex asm pic 8\" \/><\/p>\n<p>Use the following code to check the status:<\/p>\n<p><em>&nbsp; &nbsp; srvctl status asm<\/em><\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture9_5.png\" alt=\"asm flex pic 9\" \/><\/p>\n<p>Use the following code to check the cluster:<\/p>\n<p><em>&nbsp; &nbsp; crsctl check cluster&nbsp;<\/em><\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture10_3.png\" alt=\"asm flex pic 10\" \/><\/p>\n<p>Use the following code to Verify that all the instances except ASM1 are running&nbsp;on Node1 because of Flex ASM:&nbsp;<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture11_3.png\" alt=\"asm flex pic 11\" \/><\/p>\n<p>Use the following code to verify that instances are running fine on both the&nbsp;nodes even if ASM1 is down:&nbsp;<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture12_1.png\" alt=\"asm flex pic 12\" \/><\/p>\n<p>&nbsp;Use the following code to check the ADVM proxy instance:<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture13_2.png\" alt=\"asm flex pic 13\" \/><\/p>\n<p><strong>Benefits of Flex ASM&nbsp;<\/strong><\/p>\n<p>Flex ASM has the following benefits:<\/p>\n<ul>\n<li>&nbsp; &nbsp; Oracle Flex ASM supports larger LUN sizes for Oracle Database 12c clients.<\/li>\n<li>&nbsp; &nbsp; You can connect to other ASM instance from a different instance (for example,&nbsp; &nbsp;connect to a second +ASM2&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; instance from the first instance).<\/li>\n<li>&nbsp; &nbsp; You have the flexibility to rename an ASM Disk in a Disk Group. You can rename the Disk name given by Oracle&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;as needed.<\/li>\n<\/ul>\n<p><strong>About ADVM proxy instance<\/strong><\/p>\n<p>The ADVM Proxy is a special Oracle instance, which enables ADVM to connect to&nbsp;Flex ASM and is required to run on the same node as the ADVM and the ASM Cluster&nbsp;File System (ACFS).<\/p>\n<p>The ADVM Proxy instance ORACLE_SID is set to `+APX&lt;node number&gt;`.<\/p>\n<p><strong>MGMTDB &#8211; Grid Infrastructure Management Repository database<\/strong><\/p>\n<p>MGMTDB is a database instance used for storing cluster health monitor data (CHM).&nbsp;In version 11g, this information is stored in berkley database. Starting from&nbsp;version 12.1.0.2, it is part of default (mandatory) installation.<\/p>\n<p>If the existing node crashes. MGMTDB, an Oracle single instance managed by Grid&nbsp;Infrastructure, fails over to the surviving node. You can identify the current&nbsp;master using the following command:<\/p>\n<p><em>&nbsp; &nbsp; oclumon manage -get MASTER<\/em><\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture14_0.png\" alt=\"ASM flex pic 14\" \/><\/p>\n<p>This instance is managed by using the following SRVCTL commands:<\/p>\n<p><em>&nbsp; &nbsp; srvctl status mgmtdb&nbsp;<\/em><\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture15_2.png\" alt=\"asm flex pic 15\" \/><\/p>\n<p><em>&nbsp;&nbsp; &nbsp; srvctl config mgmtdb<\/em><\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture16_0.png\" alt=\"asm flex pic 16\" \/><\/p>\n<p>&nbsp;You can see the single listener associated with this database by running the&nbsp;following command:<\/p>\n<p><em>&nbsp;ps -ef|grep MGMTLSNR.<\/em><\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26544-body-Picture17_1.png\" alt=\"asm flex pic 17\" \/><\/p>\n<p>You can view information about MGMTDB from metalink doc &#8211; 1568402.1.<\/p>\n<p>By using the <em>`oclumon<\/em>` command, you can collect information about the cluster&nbsp;health.<\/p>\n<p><strong>Conclusion<\/strong><\/p>\n<p>This blog explored Oracle&#8217;s Flex ASM, the ADVM Proxy instance, and MGMTDB&nbsp;features.<\/p>\n<p>Flex ASM reduces the ASM instance footprint, running on each node of the&nbsp;cluster and also ensures high availability of your database instance, in case&nbsp;the ASM instance fails on a particular node.<\/p>\n<p>The ADVM Proxy is a special Orale instance, which enables ADVM to connect to&nbsp;Flex ASM. You can&#8217;t shutdown the ADVM Proxy unless ACFS is running.<\/p>\n<p>If the instance crashes, the MGMTDB fails over to the available node.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Exploring Flex ASM and other Oracle features<\/p>\n","protected":false},"author":2,"featured_media":7896,"menu_order":0,"comment_status":"open","ping_status":"open","template":"","format":"standard","meta":{"content-type":"","nid":"26544","content_type":"blog","created_by":"10130","authored_on":"2024-01-26T12:55:49+00:00","field_article_industries":"","tag_category":"Technical","field_blog_author_text":"by Rackspace Technology Staff","seo_description":"Understand Change Data Capture (CDC) for tracking and capturing database changes. Efficient data replication and synchronization.\r\n","field_featured_image":"","insights_image":"\/wp-content\/uploads\/2026\/blog_technical_images\/26544-insights_image-oracle-technical-blog-1-insights.jpg","field_partners":"","rxt_platforms":"Oracle","product":"","publisheddate":"2019-06-09T11:55:49","rxt_solutions":"Data, Databases","opengraph_tag":"","x_tag":"","teaser_flag":"Technical Blog","seo_titile":"Exploring Flex ASM and Other Oracle Features | Rackspace Technology","field_topics":"","field_slug":"exploring-oracle-asm-and-other-features","footnotes":""},"categories":[178],"tags":[204],"class_list":["post-7894","blogs","type-blogs","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","tag-technical"],"_links":{"self":[{"href":"https:\/\/www.rackspace.com\/en-gb\/wp-json\/wp\/v2\/blogs\/7894","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.rackspace.com\/en-gb\/wp-json\/wp\/v2\/blogs"}],"about":[{"href":"https:\/\/www.rackspace.com\/en-gb\/wp-json\/wp\/v2\/types\/blogs"}],"author":[{"embeddable":true,"href":"https:\/\/www.rackspace.com\/en-gb\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rackspace.com\/en-gb\/wp-json\/wp\/v2\/comments?post=7894"}],"version-history":[{"count":3,"href":"https:\/\/www.rackspace.com\/en-gb\/wp-json\/wp\/v2\/blogs\/7894\/revisions"}],"predecessor-version":[{"id":9750,"href":"https:\/\/www.rackspace.com\/en-gb\/wp-json\/wp\/v2\/blogs\/7894\/revisions\/9750"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.rackspace.com\/en-gb\/wp-json\/wp\/v2\/media\/7896"}],"wp:attachment":[{"href":"https:\/\/www.rackspace.com\/en-gb\/wp-json\/wp\/v2\/media?parent=7894"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rackspace.com\/en-gb\/wp-json\/wp\/v2\/categories?post=7894"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rackspace.com\/en-gb\/wp-json\/wp\/v2\/tags?post=7894"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}