The documentation should include a note instructing users to validate modified configurations before applying changes in TiKV

[mayjiang0203]

154c622

For config modification, there is config check in tiup, while no such logic for TiOperator. So we suggest add some note to describe how to validate manually here.
https://github.com/pingcap/tiup/blob/master/pkg/cluster/spec/server_config.go#L297

Since unvalidated configuration changes could cause TiKV to fail on startup.
Here is an example:

Related code: https://github.com/tikv/tikv/blob/master/components/server/src/setup.rs#L307