I am planning to set up LibreNMS to monitor around 80 devices and would like some advice on the system requirements, especially regarding storage needs. Here is the list of devices I will be monitoring:
Not easy to reply here, cause the space needed is linked to the number of sensors/metrics, not directly to the number of devices. A switch with 48 ports will more or less consume twice a 24 ports …
A Cisco 2960X 48 ports with POE monitoring enabled consumes about 150 MBytes each. That should give you an idea.
For a router, it really depends on a lot of factors, number of routing peers if you do BGP, number of ports for sure, etc etc. I have a small Cisco ISR 1100 with 4 ports which consumes 150 MBytes as well…
Best solution is to try a few of your devices, and check their disk usage. Then you can know for sure.
For Cisco WS-C3850-48T-S (Stack with two members) I have:
Size on Disk: 578.51 MiB in 431 RRD files.
For Cisco WS-C3850-48P-S (Standalone) I have:
Size on Disk: 274.83 MiB in 240 RRD files.
Cisco ASA5515 (Two running Failover/High Availability):
Size on Disk: 50.87 MiB in 72 RRD files.
Cisco AIR-CT2504-K9 with four Access Points:
Size on Disk: 51.69 MiB in 81 RRD files.
It depends on the capabilities of the device. I think it’s okay to calculate between one or two Gib per device. If switches are stacked, each stack member has to be added.
RRD files have fixed size. They will never change from their initial size.
You have to change the RRA and create a new RRD file to change the retention policy if you want to change the file size. RRD is generally pretty efficient with storage.