아래와 같이 collection을 생성할때 Core with name 'xx_shard4_replica1' already exists가 발생하는 경우 bin/solr.in.sh을 확인하여 solr.data.dir을 명시적으로 지정하지 않도록 하고 bin/solr를 이용하여 solr instance를 기동시 solr.data.dir관련 option을 지정하지 않도록 하여 default로 생성되도록 해준다. 그렇지 않으면 아래와 같이 "/user/root/solr/data/index/write.lock for client XXX.XXX.XXX.XXX already exists" Exception이 발생하면서 collection이 생성되지 않는다.

------------------------------------오류내용---------------------------

root@gsda1:~/solr/bin# ./solr create -c gc -shards 4 -replicationFactor 2

Connecting to ZooKeeper at gsda1:2181,gsda2:2181,gsda3:2181 ...
Re-using existing configuration directory gc

Creating new collection 'gc' using command:
http://localhost:8983/solr/admin/collections?action=CREATE&name=gc&numShards=4&replicationFactor=2&maxShardsPerNode=2&collection.configName=gc

ERROR: Failed to create collection 'gc' due to: {XXX.XXX.XXX.XXX:8983_solr=org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException:Error from server at http://XXX.XXX.XXX.XXX:8983/solr: Error CREATEing SolrCore 'gc_shard4_replica1': Unable to create core [gc_shard4_replica1] Caused by: /user/root/solr/data/index/write.lock for client XXX.XXX.XXX.XXX already exists
        at org.apache.hadoop.hdfs.server.namenode.FSDirWriteFileOp.startFile(FSDirWriteFileOp.java:359)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInt(FSNamesystem.java:2234)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:2154)
        at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.create(NameNodeRpcServer.java:727)
        at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.create(ClientNamenodeProtocolServerSideTranslatorPB.java:409)
        at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:447)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:989)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:845)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:788)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:422)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1807)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2455)
, XXX.XXX.XXX.XXX:8983_solr=org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException:Error from server at http://XXX.XXX.XXX.XXX:8983/solr: Error CREATEing SolrCore 'gc_shard3_replica1': Unable to create core [gc_shard3_replica1] Caused by: /user/root/solr/data/index/write.lock for client XXX.XXX.XXX.XXX already exists
        at org.apache.hadoop.hdfs.server.namenode.FSDirWriteFileOp.startFile(FSDirWriteFileOp.java:359)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInt(FSNamesystem.java:2234)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:2154)
        at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.create(NameNodeRpcServer.java:727)
        at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.create(ClientNamenodeProtocolServerSideTranslatorPB.java:409)
        at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:447)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:989)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:845)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:788)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:422)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1807)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2455)
  XXX.XXX.XXX.XXX:8983_solr=org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException:Error from server at http://XXX.XXX.XXX.XXX:8983/solr: Error CREATEing SolrCore 'gc_shard3_replica2': Unable to create core [gc_shard3_replica2] Caused by: /user/root/solr/data/index/write.lock for client XXX.XXX.XXX.XXX already exists
        at org.apache.hadoop.hdfs.server.namenode.FSDirWriteFileOp.startFile(FSDirWriteFileOp.java:359)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInt(FSNamesystem.java:2234)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:2154)
        at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.create(NameNodeRpcServer.java:727)
        at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.create(ClientNamenodeProtocolServerSideTranslatorPB.java:409)
        at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:447)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:989)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:845)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:788)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:422)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1807)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2455)
, XXX.XXX.XXX.XXX:8983_solr=org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException:Error from server at http://XXX.XXX.XXX.XXX:8983/solr: Error CREATEing SolrCore 'gc_shard4_replica2': Unable to create core [gc_shard4_replica2] Caused by: /user/root/solr/data/index/write.lock for client XXX.XXX.XXX.XXX already exists
        at org.apache.hadoop.hdfs.server.namenode.FSDirWriteFileOp.startFile(FSDirWriteFileOp.java:359)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInt(FSNamesystem.java:2234)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:2154)
        at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.create(NameNodeRpcServer.java:727)
        at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.create(ClientNamenodeProtocolServerSideTranslatorPB.java:409)
        at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:447)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:989)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:845)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:788)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:422)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1807)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2455)
}