Migrating to a different server
If the need arises Nextcloud can be migrated to a different server. A typical use case would be a hardware change or a migration from the virtual Appliance to a physical server. All migrations have to be performed with Nextcloud offline and no accesses being made. Online migration is supported by Nextcloud only when implementing industry standard clustering and HA solutions before Nextcloud is installed for the first time.
To start let us be specific about the use case. A configured Nextcloud
instance runs reliably on one machine. For some reason (e.g. more powerful
machine is available but a move to a clustered environment not yet needed)
the instance needs to be moved to a new machine. Depending on the size of
the Nextcloud instance the migration might take several hours. As a
prerequisite it is assumed that the end users reach the Nextcloud instance
via a virtual hostname (a
CNAME record in DNS) which can be pointed at
the new location. It is also assumed that the authentication method
(e.g. LDAP) remains the same after the migration.
At NO TIME any changes to the ORIGINAL system are required EXCEPT putting Nextcloud into maintenance mode.
This ensures, should anything unforseen happen you can go back to your existing installation and provide your users with a running Nextcloud while debugging the problem.
Set up the new machine with the desired OS, install and configure the Web server as well as PHP for Nextcloud (e.g. permissions or file upload size limits) and make sure the PHP version matches Nextcloud supported configuration and all relevant PHP extensions are installed. Also set up the database and make sure it is a Nextcloud supported configuration. If your original machine was installed recently just copying that base configuration is a safe best practice.
On the original machine then stop Nextcloud. First activate the maintenance mode. After waiting for 6-7 minutes for all sync clients to register the server as in maintenance mode stop the application and/or Web server that serves Nextcloud.
Copy all files from your Nextcloud instance, the Nextcloud program files, the data files, the log files and the configuration files, to the new machine (See Backup and Restoring backup). The data files should keep their original timestamp (can be done by using
-toption) otherwise the clients will re-download all the files after the migration. Depending on the original installation method and the OS the files are located in different locations. On the new system make sure to pick the appropriate locations. If you change any paths, make sure to adapt the paths in the Nextcloud config.php file. Note: This step might take several hours, depending on your installation.
Check the config.php file of the ORIGINAL system to see if it has the
data-fingerprintset to a non-empty value. If this is the case, make sure to also run the
maintenance:data-fingerprintcommand on the NEW system, similarly to how it is required when performing a backup restoration (See Restoring backup for details).
While still having Nextcloud in maintenance mode (confirm!) and BEFORE changing the
CNAMErecord in the DNS start up the database, Web server / application server on the new machine and point your web browser to the migrated Nextcloud instance. Confirm that you see the maintenance mode notice, that a logfile entry is written by both the Web server and Nextcloud and that no error messages occur. Then take Nextcloud out of maintenance mode and repeat. Log in as admin and confirm normal function of Nextcloud.
CNAMEentry in the DNS to point your users to the new location.