Before going on with this article please read https://www.nomachine.com/AR01F00497 for support entitlements when migrating to a different operating system or system. The SLA is also outlines what your entitlements are.
This article applies to NoMachine v. 4 and later.
Let's call 'machine A' the original NoMachine server host and 'machine B' the new host where you want to migrate.
Given the fact that it's not possible to migrate running sessions from one machine to another (session processes are resident in memory on the host where they have been started and cannot be moved), it's instead possible to migrate configurations. For example, if you have a multi-node server or profile rules set, you can move such settings to the new machine without the need of reconfiguring them.
Pre-requisites for migrating configurations and switching to the new machine are:
a) All the necessary system accounts are created on the new machine.
This is necessary to ensure that all users who were connecting to machine A are then able to connect to machine B.
b) NoMachine server type and version on machine B is the same installed on machine A.
Having the same server type on both machines ensures that settings from machine A can be applied on machine B. If you want to update your installation, you can do that on machine B once migration is completed
Procedure for migrating configurations is:
1) Shutdown the server (it's the 'nxserver --shutdown' command run from console).
2) Create a backup of the installationDirectory/etc/*.db files on machine A. They are, for example on Linux, the /usr/NX/etc/*.db files.
3) Copy the installationDirectory/etc/*.db files from machine A to machine B.
4) If you have changed default configurations in server.cfg and node.cfg, you have to compare the cfg file(s) from machine A with the cfg file(s) on machine B and apply the necessary changes on machine B.
Important: do not simply copy *cfg files from machine A to machine B, unless machine B is a perfect clone of machine A (i.e. it has the same operating system, version, and programs). Some configuration keys are strictly depending on the environment setting.
5) Startup the server (it's the 'nxserver --startup' command run from console).