So, I had a question regarding hardware replacement. I recently replaced several Cisco 2811 routers with Cisco ISR 4331's, and kept the same host name. After the swap, I noticed I wasn't getting any graphs for data flow on the serial interfaces. I attempted running discovery on them again, and waited for a few polling cycles, but still go no data. In the end, I ended up deleting the devices completely out of Observium, including the RRD files, and re-adding. After this was done, everything showed up correctly.
So, as I will be doing more of these soon, is there a specific process I should follow for these? Maybe rename the old device to a different hostname, then add the new device? The historical data wasn't critical, so I'm not too bothered losing it, but I would like to avoid it if possible.