This patch adds the beginning of node repair support. Repair is initiated
on a node using the REST API, for example to repair all the column families
in the "try1" keyspace, you can use:
curl -X GET --header "Content-Type: application/json" --header "Accept: application/json" "http://127.0.0.1:10000/storage_service/repair_async/try1"
I tested that the repair already works (exchanges mutations with all other
replicas, and successfully repairs them), so I think can be committed,
but will need more work to be completed
1. Repair options are not yet supported (range repair, sequential/parallel
repair, choice of hosts, datacenters and column families, etc.).
2. *All* the data of the keyspace is exchanged - Merkle Trees (or an
alternative optimization) and partial data exchange haven't been
implemented yet.
3. Full repair for nodes with multiple separate ranges is not yet
implemented correctly. E.g., consider 10 nodes with vnodes and RF=2,
so each vnode's range has a different host as a replica, so we need
to exchange each key range separately with a different remote host.
4. Our repair operation returns a numeric operation id (like Origin),
but we don't yet provide any means to use this id to check on ongoing
repairs like Origin allows.
5. Error hangling, logging, etc., needs to be improved.
6. SMP nodes (with multiple shards) should work correctly (thanks to
Asias's latest patch for SMP mutation streaming) but haven't been
tested.
7. Incremental repair is not supported (see
http://www.datastax.com/dev/blog/more-efficient-repairs)
Signed-off-by: Nadav Har'El <nyh@cloudius-systems.com>
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