Idle Cluster Seeing Increase in Replicas per Node

Just curious about something I noticed with a new cluster that I brought up. Given the holidays, I brought up an empty database + schema and let it sit and was going to get back to it later. As I got back to it, I noticed that everything was fine, but the replica’s per node just kept increasing even though the system was entirely idle:

The last updates to the database were about 8 days ago, but you’ll see from the Replica’s Per Node graph that it started somewhere around the 50 per node and now it’s close to over 100 per node. Just wondering if that’s something to be worried about and if I misconfigured anything?

Ah, this is confusing but expected. From the FAQ:

Why is disk usage increasing despite lack of writes?

The timeseries data used to power the graphs in the admin UI is stored within the cluster and accumulates for 30 days before it starts getting truncated. As a result, for the first 30 days or so of a cluster’s life you will see a steady increase in disk usage and the number of ranges in the cluster even if you aren’t writing data to it yourself.

As of the 1.0 release, there is no way to change the number of days before timeseries data gets truncated. As a workaround, however, you can start each node with the COCKROACH_METRICS_SAMPLE_INTERVAL environment variable set higher than its default of 10s to store fewer data points. For example, you could set it to 1m to only collect data every 1 minute, which would result in storing 6x less timeseries data than the default setting.

Ah ok! Makes sense! Thanks so much for the information!