Today, if a user wanted to allow a tablet to use newly added data directories, there are a few ways to achieve this:
- Drop the tablet and rewrite it.
- Copy the replica elsewhere. The copy will have a new set of data directories.
- Wait for the existing data directories in the group to run out of space – once this happens, a new directory will be added to the group.
None of these are pleasant – we should add a tool to expand the data directory group for a remote replica, maybe even allowing users to specify a target directory path.
For completeness sake, it would also be nice if the tool could reduce data directory group size, but that seems less obviously useful.