Change a Munin server and keep the data

We are migrating some servers, and we need tp change our Munin server. Most of the Munin nodes are not changed, and we would want to keep track of the historical data, if possible.

I can set up a new Munin server, but I like to know if it's possible to transfer the old data to the new server, and how to do it.

Just copy the *.rrd files in /var/lib/munin.

If you keep the same config, i.e. node names do not change in your /etc/munin/munin.conf file, then it's pretty much just a matter of moving across the contents of /var/lib/munin, which is usually where the RRD files are kept. The graphs will be re-generated from the RRD data so you don't really need those.

If your old and new server are not the same architecture, then you need to perform a dump and restore process on the RRD files rather than just copying them across, because the binary data contained in the files is different between 32-bit and 64-bit systems. In our case we decided to just stick with a regular x86 setup for the new box, so I can't comment on how well this works, but I found the following article which looks like it should work just fine: munin: migration from a 32bit to a 64bit host.

Not sure if this applies to you, but having recently done this, I also had to migrate the contents of /etc/munin/plugin-conf.d, as it contained some snmp-related stuff related to the munin-node on the old server. You might also want to look at /usr/share/munin/plugins and /etc/munin/plugins for anything custom that has been accumulated over the years.