We've had security issues in the past with it, which is why
we marked it as PROTECTED. But, modifying during runtime
is also a dangerous action. For example, when child processes
are running, persistent temp files and log files may have
unexpected effects.
A scenario for modifying dir at runtime is to migrate a disk
failure, such as using disk-based replication to migrate a node,
writing nodes.conf to save the cluster configuration.
We decided to leave it as is and add a note in the conf
about the dangers of modifying dir at runtime.
Signed-off-by: Binbin <binloveplay1314@qq.com>