{"id":7426,"date":"2020-07-08T17:30:33","date_gmt":"2020-07-08T17:30:33","guid":{"rendered":"https:\/\/rax-stg-wp-aws.com\/blogs\/sap-hana-system-replication\/"},"modified":"2026-11-03T19:28:39","modified_gmt":"2026-11-03T19:28:39","slug":"sap-hana-system-replication","status":"publish","type":"blogs","link":"https:\/\/www.rackspace.com\/de\/blogs\/sap-hana-system-replication\/","title":{"rendered":"SAP HANA system replication"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>Usually, you use system replication to support high availability and disaster&nbsp;recovery. SAP HANA&amp;reg; system replication lets you copy and continuously synchronize&nbsp;a SAP HANA database to a secondary location on the same or another data center.<\/p>\n<p>This mechanism ensures the high availability of your SAP HANA system. System replication is the SAP recommended configuration for addressing SAP HANA outage&nbsp;reduction due to planned maintenance, faults, and disasters. It supports a&nbsp;recovery point objective (RPO) of 0 seconds and a recovery time objective (RTO)&nbsp;measured in minutes.<\/p>\n<p><strong>How it works<\/strong><\/p>\n<p>After you enable SAP HANA system replication, each server process on the secondary system establishes a connection with its primary system counterpart and requests&nbsp;a snapshot of the data. From there, SAP HANA continuously replicates all logged changes in the primary system. At the same time that the system writes logs to&nbsp;the log volumes of each service, persisting the logs, it also sends them to the&nbsp;secondary system.<\/p>\n<p>The primary system commits a transaction after replicating the redo logs. This&nbsp;process depends on the replication mode that you selected when you set up the&nbsp;system replication.<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26417-body-Picture1_26.png\" alt=\"HANA Pic 1\" \/><\/p>\n<p>&nbsp;<a href=\"https:\/\/help.sap.com\/viewer\/4e9b18c116aa42fc84c7dbfd02111aba\/2.0.05\/en-US\/fb06367a182945eb9048f2b0fb788325.html\">Image Source<\/a><\/p>\n<p>\nReplication modes and operation modes play a crucial role when configuring HANA&nbsp;system replication. You need to select these modes depending on your requirements.<\/p>\n<p><strong>Replication modes<\/strong><\/p>\n<p>While registering the secondary system, you need to decide which replication mode to use. These modes generally determine how logs replicate to the secondary&nbsp;system.<\/p>\n<p>SAP HANA offers the following replication modes:<\/p>\n<p><strong>Synchronous in-memory (SYNCMEM)<\/strong><\/p>\n<p>The primary system commits the transaction only after receiving a reply that the&nbsp;secondary system received the log and stored it in the memory. The transaction&nbsp;delay in the primary system is shorter because it only includes data transmission&nbsp;time.<\/p>\n<p>Data loss can occur in the following situations:<\/p>\n<ul>\n<li>When the primary and secondary systems fail at the same time while the secondary&nbsp;system is connected, data is not written to either the primary or secondary&nbsp;system disk.<\/li>\n<li>When a takeover occurs while the secondary system is unavailable. The data that arrived on the secondary is outdated compared to the data on the primary.<\/li>\n<\/ul>\n<p>This option is vulnerable to data loss, but it provides better performance&nbsp;because it doesn&#8217;t need to wait for the secondary system disk I\/O.<\/p>\n<p><strong>Synchronous on disk (SYNC)<\/strong><\/p>\n<p>The primary system waits to commit the transaction until it gets a reply that the log is persisted on the secondary system disk. When the connection to the&nbsp;secondary system is lost, the primary system continues to process transactions&nbsp;and writes the changes to only the local disk.<\/p>\n<p>If the secondary system is connected, you won&#8217;t lose any data. However, data&nbsp;loss can occur when a takeover occurs while the secondary system is disconnected.<\/p>\n<p><strong>Synchronous full sync<\/strong><\/p>\n<p>Synchronous replication mode can run with a full sync option. The log write&nbsp;succeeds when the system writes the log buffer to the log file of both the&nbsp;primary and secondary systems. You can set the <strong>full sync<\/strong>&nbsp;option with the&nbsp;[<em>system_replication<\/em>]\/<em>enable_full_sync<\/em>&nbsp;parameter.<\/p>\n<p>When the secondary system is disconnected (for example, because of network&nbsp;failure), the primary system suspends the transaction processing until it&nbsp;reestablishes the connection to the secondary system. No data loss occurs in&nbsp;this scenario.<\/p>\n<p><strong>Asynchronous (ASYNC)<\/strong><\/p>\n<p>The primary system commits the transaction after sending the log without&nbsp;waiting for a response. This process causes no delay because the data transmission&nbsp;is asynchronous to the transaction in the primary system.<\/p>\n<p>Because you don&#8217;t need to wait for the log I\/O on the secondary system, this&nbsp;method offers better performance. The process guarantees database consistency&nbsp;across all services on the secondary system. However, it is more vulnerable to&nbsp;data loss, you might lose data changes during a takeover.<\/p>\n<p><strong>Replication mode behavior<\/strong><\/p>\n<p>The following table gives a brief idea about each replication mode&#8217;s behavior when the secondary system is not available:&nbsp;<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26417-body-Picture2_23.png\" alt=\"HANA Pic 2\" \/><\/p>\n<p><strong>Operation Modes&nbsp;<\/strong><\/p>\n<p>While registering the secondary system, you need to decide which operation mode&nbsp;to use with SAP HANA system replication. Depending on the configured operation&nbsp;mode, the database sends different types of data packages to the secondary system.<\/p>\n<p>Choose from the following operation modes:<\/p>\n<p><strong>delta_datashipping<\/strong><\/p>\n<p>This mode performs a delta data shipping occasionally (default: every 10 minutes)&nbsp;in addition to the continuous log shipping. The system does not replay the shipped&nbsp;redo log on the secondary site. During a takeover, the system replays the redo&nbsp;log up to the latest delta data shipment.<\/p>\n<p>The following image shows this traffic on the transportation channel between the primary and secondary systems for the <strong>delta_datashipping<\/strong>&nbsp;operation mode:<br \/>\n&nbsp;<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26417-body-Picture3_19.png\" alt=\"HANA Pic 3\" \/><\/p>\n<p><a href=\"https:\/\/help.sap.com\/viewer\/4e9b18c116aa42fc84c7dbfd02111aba\/2.0.05\/en-US\/dcafdb5742314873b212ebf678d6a96a.html\">Image Source<\/a>&nbsp;<\/p>\n<p><strong>logreplay<\/strong><\/p>\n<p>In this operation mode, the system does a redo log shipping after you initially&nbsp;configure system replication with one full data shipping. Then, the system&nbsp;continuously replays the redo log on the secondary site immediately after arrival.&nbsp;During a takeover, this replay process makes this step unnecessary. The&nbsp;<strong>logreplay<\/strong>&nbsp;mode does not require delta data shipping, which helps to reduce&nbsp;the amount of data transferred to the secondary system.<\/p>\n<p><strong>&nbsp;logreplay_readacess<\/strong><\/p>\n<p>You need to use this mode for replication to an Active\/Active, read-enabled,&nbsp;secondary system. It is similar to the <strong>logreplay<\/strong>&nbsp;operation mode in the&nbsp;following ways:<\/p>\n<ul>\n<li>It has continuous log shipping.<\/li>\n<li>It uses the redo log replay on the secondary system.<\/li>\n<li>It requires an initial full data shipping and a takeover.<\/li>\n<\/ul>\n<p>This mode reduces the load on the primary system because it allows read-only&nbsp;access from the secondary system.<\/p>\n<p>The following figure shows this traffic on the transportation channel between&nbsp;the primary and the secondary system for the <strong>logreplay<\/strong> and&nbsp;<strong>logreplay_readaccess<\/strong> operation modes:<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/blog_article_images\/26417-body-Picture4_16.png\" alt=\"HANA Pic 4\" \/><\/p>\n<p><a href=\"https:\/\/help.sap.com\/viewer\/4e9b18c116aa42fc84c7dbfd02111aba\/2.0.05\/en-US\/dcafdb5742314873b212ebf678d6a96a.html\">Image Source<\/a><\/p>\n<p><strong>&nbsp;Configure SAP HANA replication<\/strong><\/p>\n<p>You can configure SAP HANA system replication by using the following tools:<\/p>\n<p>&#8211; <em>SAP HANA cockpit<\/em><\/p>\n<p>&#8211; <em>SAP HANA studio<\/em><\/p>\n<p>&#8211; <em>`Hdbnsutil<\/em>` (a command-line tool)<\/p>\n<p>Perform the following steps to configure replication by using SAP HANA studio:<\/p>\n<p><strong>&nbsp;Step one: Enable system replication<\/strong><\/p>\n<p>1. Start the primary system.<\/p>\n<p>2. Perform an initial data backup or storage snapshot on the primary system.<\/p>\n<p>3. Enable system replication on the primary system by using the following steps<br \/>\n&nbsp; &nbsp;in SAP HANA studio:<\/p>\n<p>&nbsp; &nbsp; &nbsp;a. In the <strong>Systems<\/strong> view, right-click the primary system and choose<br \/>\n&nbsp; &nbsp; &nbsp;<strong>Configuration and Monitoring -&gt; Configure System Replication<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;b. The <strong>Configure System Replication<\/strong> dialog opens<br \/>\n&nbsp; &nbsp; &nbsp;and selects the <strong>Enable System Replication<\/strong> option by default. Click <strong>Next<\/strong><\/p>\n<p>&nbsp; &nbsp; &nbsp;c. Enter the logical name used to represent the primary system and click <strong>Next<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;d. Review the configured information and choose <strong>Finish<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;e. To stop the secondary system, right-click on the secondary system and choose <strong>Configuration and Monitoring -&gt; Stop System<\/strong>.<\/p>\n<p>4. To prepare the secondary system for authentication, copy the system PKI SSFS&nbsp;&nbsp; &nbsp;<strong>4<\/strong>&nbsp;and the <strong>.dat<\/strong>&nbsp;file from the primary system to the secondary system.<br \/>\n&nbsp; &nbsp;For more information, see [<a href=\"https:\/\/launchpad.support.sap.com\/#\/notes\/0002369981\">SAP Note 2369981<\/a><\/p>\n<p>5. Use the following steps to register the secondary system with the primary&nbsp;&nbsp; &nbsp;system in SAP HANA Studio:<\/p>\n<p>&nbsp; &nbsp; &nbsp;a. To stop the secondary system if it is still running, right-click the<br \/>\n&nbsp; &nbsp; &nbsp;secondary system and choose <strong>Configuration and Monitoring -&gt;Stop System<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;b. In the <strong>Systems<\/strong>&nbsp;view, right-click the secondary system and choose<br \/>\n&nbsp; &nbsp; &nbsp;<strong>Configuration and Monitoring -&gt; Configure System Replication<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;c. In the <strong>Configure System Replication<\/strong>&nbsp;dialog, choose<br \/>\n&nbsp; &nbsp; &nbsp;<strong>Register Secondary System<\/strong>&nbsp;and click <strong>Next<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;d. Enter the system information and the logical name for the secondary system.<\/p>\n<p>&nbsp; &nbsp; &nbsp;e. Specify the log replication mode and operation mode.<\/p>\n<p>&nbsp; &nbsp; &nbsp;f. Review the configured information and click <strong>Finish<\/strong>.<\/p>\n<p>6. The secondary system requests an initial full data replica from the primary system.<\/p>\n<p>The system replication is enabled and the secondary system is registered with a<br \/>\nprimary system now<\/p>\n<p><strong>Step two: &nbsp;Disable system replication<\/strong><\/p>\n<p><strong>1. Use the following steps to unregister the secondary system in SAP HANA studio:<\/strong><\/p>\n<p>&nbsp; &nbsp; &nbsp;a. In the <strong>Systems<\/strong>&nbsp;view, right-click the primary system and choose<br \/>\n&nbsp; &nbsp; &nbsp;<strong>Configuration and Monitoring -&gt; Configure System Replication<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;b. In the <strong>Configure System Replication dialog<\/strong>, choose<br \/>\n&nbsp; &nbsp; &nbsp;<strong>Unregister secondary system<\/strong>&nbsp;and click <strong>Next<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;c. Enter the required system information and click <strong>Next<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;d. Review the configured information and click <strong>Finish<\/strong>.<\/p>\n<p>&nbsp;<\/p>\n<p><strong>2. Use the following steps to disable replication system on the primary system:<\/strong><\/p>\n<p>&nbsp; &nbsp; &nbsp;a. In the <strong>Systems<\/strong>&nbsp;view, right-click the primary system and choose<br \/>\n&nbsp; &nbsp; &nbsp;<strong>Configuration and Monitoring -&gt; Configure System Replication<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;b. Choose <strong>Disable system replication<\/strong>&nbsp;and click <strong>Next<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;c. Review the configured information and click <strong>Finish.<\/strong><\/p>\n<p><strong>Step three: Takeover the secondary system<\/strong><\/p>\n<p>The takeover process switches your active system from the current primary system&nbsp;to the secondary system. If you perform a takeover as part of a planned downtime,&nbsp;you should first make sure that the primary system has completely stopped before<br \/>\nperforming a takeover to the secondary system.&nbsp;<\/p>\n<p>1. Perform a takeover in the secondary system at data center <strong>B<\/strong>&nbsp;by using the&nbsp;following steps in SAP HANA studio:<\/p>\n<p>&nbsp; &nbsp; &nbsp;a. In the <strong>Systems<\/strong>&nbsp;view, right-click the secondary system and choose<br \/>\n&nbsp; &nbsp; &nbsp;<strong>Configuration and Monitoring -&gt; Configure System Replication<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;b. Choose <strong>Perform Takeover<\/strong> from the actions list.<\/p>\n<p>&nbsp; &nbsp; &nbsp;c. Enter the required system information and click <strong>Next<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;d. Review the information and click <strong>Finish<\/strong>.<\/p>\n<p>&nbsp;<\/p>\n<p>2. At this point, the Secondary system becomes the production system. If the&nbsp;system is running, it leaves the recovery mode and becomes fully operational,&nbsp;replaying the latest transaction logs and accepting queries. If the system is offline, start it, and it will take over production operations.<\/p>\n<p><strong>Step four: Failback to the original primary system<\/strong><\/p>\n<p>1. To failback, you must attach your former primary system as the new secondary&nbsp;&nbsp;system to the current primary system by using the following steps in SAP HANA&nbsp;&nbsp; studio:<\/p>\n<p>&nbsp; &nbsp; &nbsp;a. In the <strong>Systems<\/strong> view, right-click the primary system and choose<br \/>\n&nbsp; &nbsp; &nbsp;<strong>Configuration and Monitoring -&gt; Configure System Replication<\/strong>.<\/p>\n<p>&nbsp; &nbsp; &nbsp;b. In the <strong>Configure System Replication<\/strong> dialog, choose<br \/>\n&nbsp; &nbsp; &nbsp;<strong>Register for Secondary System<\/strong> and click <strong>Next<\/strong><\/p>\n<p>&nbsp; &nbsp; &nbsp;c. Enter the system information and the logical name for the system.<\/p>\n<p>&nbsp; &nbsp; &nbsp;d. Specify log replication mode and operation mode as required.<\/p>\n<p>&nbsp; &nbsp; &nbsp;e. Review the configured information and click <strong>Finish<\/strong>.<\/p>\n<p>2. The former primary system is now registered as the secondary system with the&nbsp;current primary system, formerly the secondary system. Because the system&nbsp;cannot use the data in the former primary system, it carries out a complete<br \/>\n&nbsp; &nbsp;initialization. A full data replication runs until the previous primary system&nbsp;is entirely in sync.<\/p>\n<p>3. Verify that the secondary system replication status in All Services is active&nbsp;and in sync. You can see this status in the Administration editor on the&nbsp;<strong>Overview<\/strong>&nbsp;tab.<br \/>\n&nbsp;<\/p>\n<p><strong>Conclusion<\/strong><\/p>\n<p>By using system replication, you can ensure high availability and enable disaster&nbsp;recovery for your SAP HANA system. Achieve this by continuously replicating the&nbsp;data from a primary to a secondary system, including in-memory loading. System&nbsp;replication facilitates rapid failover in the event of a disaster. The main&nbsp;advantage of SAP HANA replication is a zero-second RPO and an RTO of mere minutes.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>SAP HANA system replication<\/p>\n","protected":false},"author":2,"featured_media":7428,"menu_order":0,"comment_status":"open","ping_status":"open","template":"","format":"standard","meta":{"content-type":"","nid":"26417","content_type":"blog","created_by":"10130","authored_on":"2023-12-27T18:30:33+00:00","field_article_industries":"","tag_category":"Technical","field_blog_author_text":"by Chakrala Vinodh, SAP Database Administrator, Rackspace Technology","seo_description":"Explore SAP HANA system replication for high availability and disaster recovery. Enhance system resilience through continuous synchronization.\r\n","field_featured_image":"","insights_image":"\/wp-content\/uploads\/2026\/blog_technical_images\/26417-insights_image-erp-technical-blog-1-insights.jpg","field_partners":"","rxt_platforms":"SAP","product":"","publisheddate":"2020-07-08T17:30:33","rxt_solutions":"Enterprise Resource Planning (ERP), Data Modernization","opengraph_tag":"","x_tag":"","teaser_flag":"Technical Blog","seo_titile":"SAP HANA Replication | Rackspace Technology","field_topics":"","field_slug":"sap-hana-system-replication","footnotes":""},"categories":[178],"tags":[204],"class_list":["post-7426","blogs","type-blogs","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","tag-technical"],"_links":{"self":[{"href":"https:\/\/www.rackspace.com\/de\/wp-json\/wp\/v2\/blogs\/7426","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.rackspace.com\/de\/wp-json\/wp\/v2\/blogs"}],"about":[{"href":"https:\/\/www.rackspace.com\/de\/wp-json\/wp\/v2\/types\/blogs"}],"author":[{"embeddable":true,"href":"https:\/\/www.rackspace.com\/de\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rackspace.com\/de\/wp-json\/wp\/v2\/comments?post=7426"}],"version-history":[{"count":3,"href":"https:\/\/www.rackspace.com\/de\/wp-json\/wp\/v2\/blogs\/7426\/revisions"}],"predecessor-version":[{"id":9452,"href":"https:\/\/www.rackspace.com\/de\/wp-json\/wp\/v2\/blogs\/7426\/revisions\/9452"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.rackspace.com\/de\/wp-json\/wp\/v2\/media\/7428"}],"wp:attachment":[{"href":"https:\/\/www.rackspace.com\/de\/wp-json\/wp\/v2\/media?parent=7426"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rackspace.com\/de\/wp-json\/wp\/v2\/categories?post=7426"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rackspace.com\/de\/wp-json\/wp\/v2\/tags?post=7426"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}