neo4j-server Unable to lock store Error

CentOSでpython neo4j-embedded-1.6を使ってDBに書きこもうとすると以下のエラー
が発生したのでメモる。

DEBUG:root:trans_contents start
org.neo4j.graphdb.TransactionFailureException: Could not create data source [nioneodb], see nested exception for cause of error
	at org.neo4j.kernel.impl.transaction.TxModule.registerDataSource(TxModule.java:161)
	at org.neo4j.kernel.GraphDbInstance.start(GraphDbInstance.java:104)
	at org.neo4j.kernel.EmbeddedGraphDbImpl.(EmbeddedGraphDbImpl.java:187)
	at org.neo4j.kernel.EmbeddedGraphDatabase.(EmbeddedGraphDatabase.java:80)
Caused by: java.lang.IllegalStateException: Unable to lock store [/vol/tools/neo4j-community-1.4.M01/data/graph.db/neostore], this is usually a result of some other Neo4j kernel running using the same store.
	at org.neo4j.kernel.impl.nioneo.store.CommonAbstractStore.checkStorage(CommonAbstractStore.java:174)
	at org.neo4j.kernel.impl.nioneo.store.CommonAbstractStore.(CommonAbstractStore.java:102)
	at org.neo4j.kernel.impl.nioneo.store.AbstractStore.(AbstractStore.java:119)
	at org.neo4j.kernel.impl.nioneo.store.NeoStore.(NeoStore.java:78)
	at org.neo4j.kernel.impl.nioneo.xa.NeoStoreXaDataSource.(NeoStoreXaDataSource.java:165)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
	at org.neo4j.kernel.impl.transaction.XaDataSourceManager.create(XaDataSourceManager.java:77)
	at org.neo4j.kernel.impl.transaction.TxModule.registerDataSource(TxModule.java:155)

同じプロセスが動いている可能性がある。

$ ps -aux | grep neo4j
[neo4j@ip-10-156-117-25 uki2neo4j]$ ps aux | grep neo4j
root     12423  0.0  2.4 421668 41424 ?        Sl   12:15   0:06 java -Dwrapper.pidfile=/vol/tools/neo4j-community-1.4.M01/data/neo4j-server.pid -Dwrapper.service=true -Dwrapper.visible=false -Xrs -jar /vol/tools/neo4j-community-1.4.M01/bin/wrapper.jar -c /vol/tools/neo4j-community-1.4.M01/conf/neo4j-wrapper.conf
neo4j    13263  2.6  2.0 420156 34608 pts/1    Sl+  20:33   0:00 java -Dwrapper.pidfile=/vol/tools/neo4j-community-1.4.M01/data/neo4j-server.pid -Dwrapper.service=true -Dwrapper.visible=false -jar /vol/tools/neo4j-community-1.4.M01/bin/wrapper.jar -px /vol/tools/neo4j-community-1.4.M01/conf/neo4j-wrapper.conf
一度殺して再起動させてみたらこの問題はクリア。

参考：
Pythonスタートブック
みんなのPython