Rolling Upgrades
Users with highly available clusters under heavy transaction loads may want to upgrade to a newer version of MarkLogic in a seamless manner. A rolling upgrade, where hosts in a cluster are upgraded one by one, is one approach to addressing this need. Rolling upgrades are used to upgrade a large cluster with many hosts to a newer version of MarkLogic Server without incurring any downtime in availability or interruption of transactions. A rolling upgrade may also be used to apply patches to multiple hosts.
The goal in performing a rolling upgrade is to have zero downtime of your server availability or transactional data. This is most useful for large high availability (HA) clusters that have a large number of ongoing transactions. A rolling upgrade can be performed on both a primary cluster and a disaster recovery (DR) cluster.
Your cluster must have MarkLogic 8.0-6 or later installed to perform a rolling upgrade. The rolling upgrade feature works on all supported platforms. Rolling upgrades will only work when upgrading from MarkLogic 8.0-6 or later to MarkLogic 10.0-x or later.
Note
Do not change your application to take advantage of any 10.0-1 features until all the nodes in your cluster have been upgraded to 10.0-1. In addition, you should avoid making any configuration changes to your cluster during a rolling upgrade.
This section describes rolling upgrades