Upgrade AEM 6.2 to AEM 6.4

AEM instance can be upgraded to a 6.4 version in two ways.

1. New AEM 6.4 setup
2. In-place upgrade

Let's c In-place upgrade process.

In-place up-gradation Process:

1. Start your AEM 6.2 instance.
2. Check all consoles are working fine.
3. Remove all custom code and configs.
4. Check “quickstart.properties” file is present under /crx-quickstart/conf. If not, copy from other instances and paste it in the above location.
5. Run offline compaction to reduce repository size. Check how to run offline compaction.
6. Goto packageshare and download the package pre-upgrade-package-cq62-1.2.zip

Navigate to package manager and install the
pre-upgrade-package-cq62-1.2.zip

Once package is installed, navigate to OSGI Config Manager. Search for "preupgrade". Look for com.adobe.aem.upgrade.prechecks.mbean.impl.PreUpgradeTasksMBeanImpl.

Let's see what these are parameters do:
VersionPurge: This can be used to purge page versions.
GenerateBundlesListFileTask: List of bundles will be checked and placed in some path. This path can be found in your log.
DisableReplication: Disable replication agents
WorkflowPurgeTask: Purge workflow. I not used while performing upgrade as I don’t have any workflow purge settings.
com.day.cq.audit.impl.AuditLogMaintenanceTask: Audit log in logger.
NOTE: If you run any task which you not configured then the pre-upgrade task gets fail.
10. Once all necessary settings are added, open JMX console and select “PreUpgradeTasks”.

11. Open error.log and check below entries in logs

23.09.2018 11:30:55.155 *INFO* [sling-threadpool-afcaa079-0115-490c-885f-2041bf40c356-(apache-sling-job-thread-pool)-1-Pre Upgrade Tasks Queue(com/adobe/aem/preupgrade/job/RunAllPreUpgradeTasks)] 

com.adobe.aem.upgrade.prechecks.tasks.impl.RunAllPreUpgradeTasksImpl com.day.cq.wcm.core.impl.VersionPurgeTask task finished running successfully.

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23.09.2018 11:31:05.455 *INFO* [sling-threadpool-afcaa079-0115-490c-885f-2041bf40c356-(apache-sling-job-thread-pool)-1-Pre Upgrade Tasks Queue(com/adobe/aem/preupgrade/job/RunAllPreUpgradeTasks)] 

com.adobe.aem.upgrade.prechecks.tasks.impl.RunAllPreUpgradeTasksImpl WorkflowPurgeTask task finished running successfully.

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23.09.2018 11:31:16.118 *INFO* [sling-threadpool-afcaa079-0115-490c-885f-2041bf40c356-(apache-sling-job-thread-pool)-1-Pre Upgrade Tasks Queue(com/adobe/aem/preupgrade/job/RunAllPreUpgradeTasks)] 

com.adobe.aem.upgrade.prechecks.tasks.impl.RunAllPreUpgradeTasksImpl GenerateBundlesListFileTask task finished running successfully.

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23.09.2018 11:31:21.229 *INFO* [sling-threadpool-afcaa079-0115-490c-885f-2041bf40c356-(apache-sling-job-thread-pool)-1-Pre Upgrade Tasks Queue(com/adobe/aem/preupgrade/job/RunAllPreUpgradeTasks)] 

com.adobe.aem.upgrade.prechecks.tasks.impl.RunAllPreUpgradeTasksImpl DisableReplicationAgentsTask task finished running successfully.

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23.09.2018 11:31:21.229 *ERROR* [sling-threadpool-afcaa079-0115-490c-885f-2041bf40c356-(apache-sling-job-thread-pool)-1-Pre Upgrade Tasks Queue(com/adobe/aem/preupgrade/job/RunAllPreUpgradeTasks)] 

com.adobe.aem.upgrade.prechecks.tasks.impl.RunAllPreUpgradeTasksImpl RunAllPreUpgradeTasks task finished running successfully.

12. Stop AEM 6.2 server and remove files under crx-quickstart/launchpad/installer.13. Place your AEM 6.4 jar in the same place where AEM 6.2.jar placed.

14. Run the below command:

D:\CQ5\CQ5\AEM6.2>java -Xmx4096m -jar AEM_6.4_Quickstart.jar -unpack

Once done successfully we will be getting below message
Quickstart files unpacked, server startup scripts can be found under //crx-quickstart/bin


15. Run below command to change the repository to segment tar.

D:\CQ5\CQ5\AEM6.2>java -Xmx4096m -jar AEM_6.4_Quickstart.jar -v -x crx2oak -xargs - -load-profile segment-no-ds

23.09.2018 12:17:34.203 INFO c.a.g.c.e.MigrationRunner: migration completed

 __   __         __        ___ ___  ___  __

/  ` /  \  |\/| |__) |    |__   |  |__  |  \

\__, \__/  |  | |    |___ |___  |  |___ |__/

16. Start AEM 6.4.
17. It starts a new segment tar repository and also performs re-indexing. Grab some coffee and wait till you see the below message in the log.

org.apache.jackrabbit.oak.plugins.index.IndexUpdate Reindexing completed

18. Navigate to product information console to see the product version.