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Knowledgebase: MarkLogic Server
MarkLogic Server Version Downgrades are Not Supported
21 December 2015 10:38 AM

Summary

Version downgrades are not supported by MarkLogic Server.

Backup your configuration files before you do anything else

Please ensure you have all your current configuration files backed up.

Each host in a MarkLogic cluster is configured using parameters which are stored in XML Documents that are available on each host. These are usually relatively small files and will zip up to a manageable size.

If you cd to your "Data" directory (on Linux this is /var/opt/MarkLogic; on Windows this is C:\Program Files\MarkLogic\Data and on OS X this is /Users/{username}/Library/Application Support/MarkLogic), you should see several xml files (assignments, clusters, databases, groups, hosts, server).

Whenever MarkLogic updates any of these files, it creates a backup using the same naming convention used for older ErrorLog files (_1, _2 etc). We recommend backing up all configuration files before following the steps under the next heading.

Upgrade Guidelines:

If you follow these upgrade guidelines and recommendations, then it is unlikely that you will need to downgrade your MarkLogic Server instance.

  • Stay current with upgrades. MarkLogic Server typically gets faster and more stable with each release.  
  • Upgrade to the latest maintenance release of your current version before upgrading to the next feature version (for example: when upgrading from v6.0-2 to v7.0-2.3, first upgrade to the latest 6.0-x release). This may be required for older maintenance releases.
  • [Note] Upgrading across 2 feature releases in a single step may not be supported - please refer to the Installation and Upgrade Guide for supported upgrade paths.
  • When planning an upgrade across feature releases of MarkLogic Server, plan for a full test cycle of your application.
  • In addition to testing your application on the new version, test the upgrade process.
  • Always read the release notes before performing an upgrade. Pay particular attention to the "Known Incompatibilities" section.

Back-out Plan

Although it is not expected that you will ever need to back out a version upgrade of MarkLogic Server, it is always prudent to have a contingency plan for the worst case scenario.

Before an upgrade, you will want to

  • Create a backup of all of your forests in all of your databases.
  • Save your deployment scripts (used for creating your system configuration)

In the unlikely event you want to restore your system to a previous version level, you will need to first make a decision regarding the data in your databases.

MarkLogic does not support restoring a backup made on a newer version of MarkLogic Server onto an older version of MarkLogic Server. Your Back-Out Plan will need to take this into consideration.

  • If it is sufficient to roll back to the data as it existed previous to the upgrade, you will be able to just restore the data from the backup you made prior to the upgrade;
  • If you can recreate / reload all of the data that was inserted after the upgrade, you can restore the data from the pre-upgrade backup and then reload / recreate the new data;
  • If you need to capture the current data as it now exists in the database, you can use a tool like XQSync to backup the database contents to a Zip file, and then use XQSync again to load this backup;

Once you have decided how to handle your data, you will need to recreate your MarkLogic Instance from a fresh install.  This can be done on fresh hardware, or in place if you are careful with your data. The steps will include

  • Uninstall MarkLogic on each host
  • Remove any previous instance of MarkLogic data and configuration files from each host.
  • Install MarkLogic Server.
  • Recreate your configuration
  • Restore your data using the method you decided on previously.

In addition to testing an upgrade, you should also test your Back-Out Plan.

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