Hey, my cluster is also "Not Ready or Lagging" and it's taking TOO long to get back. Also in the middle of it I started a configuration change. My question is, is the configuration change in progress while the server is down?

Copy-pasting my response from our email thread, so others might find it useful in the future: The amount of time it takes for reindexing data either after a crash or after a config change depends on the amount of data in the cluster and the volume of pending write batches since the last hourly snapshot. To avoid extended downtimes in the future, I would recommend considering enabling High Availability on your cluster, so that even if one node has an issue and has to restart, the other two will continue servicing traffic.

is the configuration change in progress while the server is down?

In this specific case, yes the config change was able to proceed, even as the node was down.