Ignore #6, and #7, they seem to comply with behavior in #8,  

however, setting wsrep_provider to galera library doesn't go down well.

=============================
Version: '5.5.33-23.7.5-debug'  socket: '/pxc/datadir/pxc.sock'  port: 4000  Percona XtraDB Cluster (GPL) 5.5.33-23.7.5, Revision 465, wsrep_23.7.5.r465
130816  7:30:52 [Note] WSREP: wsrep_notify_cmd is not defined, skipping notification.
130816  7:30:52 [Note] WSREP: Assign initial position for certification: 38570, protocol version: 2
130816  7:30:52 [Note] WSREP: Synchronized with group, ready for connections
130816  7:30:52 [Note] WSREP: wsrep_notify_cmd is not defined, skipping notification.
130816  7:30:54 [Note] WSREP: Stop replication
130816  7:30:54 [Note] WSREP: Closing send monitor...
130816  7:30:54 [Note] WSREP: Closed send monitor.
130816  7:30:54 [Note] WSREP: gcomm: terminating thread
130816  7:30:54 [Note] WSREP: gcomm: joining thread
130816  7:30:54 [Note] WSREP: gcomm: closing backend
130816  7:30:54 [Note] WSREP: view((empty))
130816  7:30:54 [Note] WSREP: Received self-leave message.
130816  7:30:54 [Note] WSREP: gcomm: closed
130816  7:30:54 [Note] WSREP: Flow-control interval: [0, 0]
130816  7:30:54 [Note] WSREP: Received SELF-LEAVE. Closing connection.
130816  7:30:54 [Note] WSREP: Shifting SYNCED -> CLOSED (TO: 38570)
130816  7:30:54 [Note] WSREP: RECV thread exiting 0: Success
130816  7:30:54 [Note] WSREP: New cluster view: global state: dd00df13-e87a-11e2-0800-5cbe45ea7ee5:38570, view# -1: non-Primary, number of nodes: 0, my index: -1, protocol version 2
130816  7:30:54 [Note] WSREP: recv_thread() joined.
130816  7:30:54 [Note] WSREP: Closing replication queue.
130816  7:30:54 [Note] WSREP: Closing slave action queue.
130816  7:30:54 [Note] WSREP: wsrep_notify_cmd is not defined, skipping notification.
130816  7:30:54 [Note] WSREP: applier thread exiting (code:0)
130816  7:30:54 [Note] WSREP: applier thread exiting (code:5)
130816  7:30:56 [Note] WSREP: rollbacker thread exiting
130816  7:30:56 [Note] WSREP: dtor state: CLOSED
130816  7:30:56 [Note] WSREP: apply mon: entered 0
130816  7:30:56 [Note] WSREP: apply mon: entered 0
130816  7:30:56 [Note] WSREP: mon: entered 3 oooe fraction 0 oool fraction 0
130816  7:30:56 [Note] WSREP: cert index usage at exit 0
130816  7:30:56 [Note] WSREP: cert trx map usage at exit 0
130816  7:30:56 [Note] WSREP: deps set usage at exit 0
130816  7:30:56 [Note] WSREP: avg deps dist 0
130816  7:30:56 [Note] WSREP: wsdb trx map usage 0 conn query map usage 0
130816  7:30:56 [Note] WSREP: Shifting CLOSED -> DESTROYED (TO: 38570)
130816  7:30:56 [Note] WSREP: Flushing memory map to disk...
130816  7:30:56 [Note] WSREP: Initial position: dd00df13-e87a-11e2-0800-5cbe45ea7ee5:38570
130816  7:30:56 [Note] WSREP: wsrep_load(): loading provider library 'none'
130816  7:30:56 [ERROR] WSREP: Failed to get provider options
130816  7:31:10 [Note] WSREP: Stop replication
130816  7:31:12 [Note] WSREP: Initial position: dd00df13-e87a-11e2-0800-5cbe45ea7ee5:38570
130816  7:31:12 [Note] WSREP: wsrep_load(): loading provider library '/pxc/lib/libgalera_smm.so'
130816  7:31:12 [Note] WSREP: wsrep_load(): Galera 2.6(r300) by Codership Oy <email address hidden> loaded succesfully.
130816  7:31:12 [Note] WSREP: Found saved state: dd00df13-e87a-11e2-0800-5cbe45ea7ee5:38570
130816  7:31:12 [Note] WSREP: Reusing existing '/pxc/datadir//galera.cache'.
130816  7:31:12 [Note] WSREP: Passing config to GCS: base_host = 127.0.0.1; base_port = 4567; cert.log_conflicts = no; gcache.dir = /pxc/datadir/; gcache.keep_pages_size = 0; gcache.mem_size = 0; gcache.name = /pxc/datadir//galera.cache; gcache.page_size = 128M; gcache.size = 128M; gcs.fc_debug = 0; gcs.fc_factor = 1; gcs.fc_limit = 16; gcs.fc_master_slave = NO; gcs.max_packet_size = 64500; gcs.max_throttle = 0.25; gcs.recv_q_hard_limit = 9223372036854775807; gcs.recv_q_soft_limit = 0.25; gcs.sync_donor = NO; replicator.causal_read_timeout = PT30S; replicator.commit_order = 3
130816  7:31:12 [Note] WSREP: Assign initial position for certification: 38570, protocol version: -1

===========================================================

After this when I do anything on mysql prompt, I  get 'Unknown command'.

But it still responds to SIGQUIT for shutdown.

So the question is,


a) Is the behavior of changing the provider from library to none and back to libary defined? (May be useful to restart the backend)

b) If not then the above should be fine.

c) If it is defined,  then currently it shuts down fine but setting wsrep_provider back to library  has no use since the SQL commands don't work, so mysql has to be shutdown.