Online Upgrades

You can upgrade your cluster without taking your cluster down so that your application can continue running. Using this upgrade method, you add a new node then remove an older node from a cluster. You then perform a swap rebalance. You continue this process until you replace all old nodes with new nodes. For more information on swap rebalance, see Section 5.7.3, “Swap Rebalance”.

Online upgrades may take a while because each node must be taken out of the cluster, upgraded to a current version, and then brought back into the cluster. However because you can upgrade the cluster without taking it cluster down, you may prefer this upgrade method.

For instructions on online upgrades, see Section 2.5.1, “Online Upgrades” .

Offline Upgrades

For offline upgrades, you shut down your application first so that no more incoming data arrives. Then you shut down each Couchbase Server node and verify the disk write queue is 0. This way you know that Couchbase Server stored all items onto disk from RAM during shutdown.

Then you perform an install of the latest version of Couchbase onto a machine. The installer will automatically detect the data files from the older install and convert them to the correct format, if needed.

Offline upgrades can be quicker because the upgrade process can take place simultaneously on every node in the cluster. The cluster, though, must be shut down for the upgrade to take place. This disables both the cluster and all the applications built on it.

For full instructions on performing an offline upgrade, see Section 2.5.3, “Offline Upgrade Process” .