it looks that by specifying replace_token, the old owner is not removed from gossip (which I had thought it would do). Then it's understandable that the old owner would resurface later and we get some warning saying that the same token is owned by both.
I ran an example with a 2-node cluster, with RF=2. host 10.72.201.80 was running for a while and had some data, then i shut it down, and booted up 10.190.221.204 with replace_token of the old token owned by the previous host. the following log sequence shows that the new host does acquire the token, but it does not at the same time remove 80 forcefully from gossip. instead, a few seconds later, it believed that .80 became live again. I don't have much understanding of the Gossip protocol, but roughly know that it's probability-based, looks we need an "assertive"/"NOW" membership control message for replace_token. thanks yang WARN [main] 2012-09-10 08:00:21,855 TokenMetadata.java (line 160) Token 166594924822352415786406422619018814804 changing ownership from / 10.72.201.80 to /10.190.221.204 INFO [main] 2012-09-10 08:00:21,855 StorageService.java (line 753) JOINING: Starting to bootstrap... INFO [CompactionExecutor:2] 2012-09-10 08:00:21,875 CompactionTask.java (line 109) Compacting [SSTableReader(path='/mnt/cassandra/data/system/LocationInfo/system-LocationInfo-hd-1-Data.db'), SSTableReader(path='/mnt/cassandra/data/system/LocationInfo/system-LocationInfo-hd-3-Data.db'), SSTableReader(path='/mnt/cassandra/data/system/LocationInfo/system-LocationInfo-hd-4-Data.db'), SSTableReader(path='/mnt/cassandra/data/system/LocationInfo/system-LocationInfo-hd-2-Data.db')] INFO [CompactionExecutor:2] 2012-09-10 08:00:21,979 CompactionTask.java (line 221) Compacted to [/mnt/cassandra/data/system/LocationInfo/system-LocationInfo-hd-5-Data.db,]. 499 to 394 (~78% of original) bytes for 3 keys at 0.003997MB/s. Time: 94ms. INFO [Thread-4] 2012-09-10 08:00:22,070 StreamInSession.java (line 214) Finished streaming session 1 from /10.72.102.61 INFO [main] 2012-09-10 08:00:22,073 ColumnFamilyStore.java (line 643) Enqueuing flush of Memtable-LocationInfo@30624226(77/96 serialized/live bytes, 2 ops) INFO [FlushWriter:2] 2012-09-10 08:00:22,074 Memtable.java (line 266) Writing Memtable-LocationInfo@30624226(77/96 serialized/live bytes, 2 ops) INFO [FlushWriter:2] 2012-09-10 08:00:22,082 Memtable.java (line 307) Completed flushing /mnt/cassandra/data/system/LocationInfo/system-LocationInfo-hd-6-Data.db (163 bytes) for commitlog position ReplayPosition(segmentId=6360937126265, position=3854) INFO [main] 2012-09-10 08:00:22,087 StorageService.java (line 1098) Node / 10.190.221.204 state jump to normal INFO [main] 2012-09-10 08:00:22,088 StorageService.java (line 666) Bootstrap/Replace/Move completed! Now serving reads. INFO [main] 2012-09-10 08:00:22,089 Mx4jTool.java (line 72) Will not load MX4J, mx4j-tools.jar is not in the classpath INFO [main] 2012-09-10 08:00:22,119 CassandraDaemon.java (line 124) Binding thrift service to /10.190.221.204:9160 INFO [main] 2012-09-10 08:00:22,122 CassandraDaemon.java (line 133) Using TFastFramedTransport with a max frame size of 15728640 bytes. INFO [main] 2012-09-10 08:00:22,125 CassandraDaemon.java (line 160) Using synchronous/threadpool thrift server on /10.190.221.204 : 9160 INFO [Thread-5] 2012-09-10 08:00:22,125 CassandraDaemon.java (line 212) Listening for thrift clients... INFO [RMI TCP Connection(4)-127.0.0.1] 2012-09-10 08:00:59,014 ColumnFamilyStore.java (line 643) Enqueuing flush of Memtable-Versions@11775580(128/160 serialized/live bytes, 3 ops) INFO [FlushWriter:2] 2012-09-10 08:00:59,016 Memtable.java (line 266) Writing Memtable-Versions@11775580(128/160 serialized/live bytes, 3 ops) INFO [FlushWriter:2] 2012-09-10 08:00:59,024 Memtable.java (line 307) Completed flushing /mnt/cassandra/data/system/Versions/system-Versions-hd-1-Data.db (256 bytes) for commitlog position ReplayPosition(segmentId=6360937126265, position=3854) INFO [GossipStage:1] 2012-09-10 08:01:23,036 Gossiper.java (line 850) Node /10.72.201.80 is now part of the cluster INFO [GossipStage:1] 2012-09-10 08:01:23,037 Gossiper.java (line 816) InetAddress /10.72.201.80 is now UP INFO [GossipStage:1] 2012-09-10 08:01:23,038 StorageService.java (line 1126) Nodes /10.72.201.80 and /10.190.221.204 have the same token 166594924822352415786406422619018814804. Ignoring /10.72.201.80 INFO [GossipTasks:1] 2012-09-10 08:01:32,967 Gossiper.java (line 830) InetAddress /10.72.201.80 is now dead. INFO [GossipTasks:1] 2012-09-10 08:01:53,976 Gossiper.java (line 644) FatClient /10.72.201.80 has been silent for 30000ms, removing from gossip
