打开文件数（lsof | wc -l）：20484
ulimit是无限的
CONSOLE.LOG
Caused by: java.io.FileNotFoundException: /home/centos/neo4j-community-2.2.3/data/graph.db/schema/label/lucene/_179hu.fdt (Permission denied)
at java.io.RandomAccessFile.open(Native Method) ~[na:1.7.0_85]
at java.io.RandomAccessFile.<init>(RandomAccessFile.java:241) ~[na:1.7.0_85]
at org.apache.lucene.store.FSDirectory$FSIndexOutput.<init>(FSDirectory.java:441) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.store.FSDirectory.createOutput(FSDirectory.java:306) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.FieldsWriter.<init>(FieldsWriter.java:83) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.StoredFieldsWriter.initFieldsWriter(StoredFieldsWriter.java:64) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.StoredFieldsWriter.finishDocument(StoredFieldsWriter.java:107) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.StoredFieldsWriter$PerDoc.finish(StoredFieldsWriter.java:151) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.DocumentsWriter$WaitQueue.writeDocument(DocumentsWriter.java:1404) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.DocumentsWriter$WaitQueue.add(DocumentsWriter.java:1424) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.DocumentsWriter.finishDocument(DocumentsWriter.java:1043) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.DocumentsWriter.updateDocument(DocumentsWriter.java:772) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.IndexWriter.updateDocument(IndexWriter.java:2328) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.IndexWriter.updateDocument(IndexWriter.java:2300) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.neo4j.kernel.api.impl.index.LuceneIndexWriter.updateDocument(LuceneIndexWriter.java:67) ~[neo4j-lucene-index-2.2.3.jar:2.2.3]
at org.neo4j.kernel.api.impl.index.TrackingLuceneIndexWriter.updateDocument(TrackingLuceneIndexWriter.java:55) ~[neo4j-lucene-index-2.2.3.jar:2.2.3]
at org.neo4j.kernel.api.impl.index.LuceneLabelScanStore.updateDocument(LuceneLabelScanStore.java:150) ~[neo4j-lucene-index-2.2.3.jar:2.2.3]
at org.neo4j.kernel.api.impl.index.LuceneLabelScanWriter.flush(LuceneLabelScanWriter.java:156) ~[neo4j-lucene-index-2.2.3.jar:2.2.3]
at org.neo4j.kernel.api.impl.index.LuceneLabelScanWriter.write(LuceneLabelScanWriter.java:75) ~[neo4j-lucene-index-2.2.3.jar:2.2.3]
at org.neo4j.kernel.impl.transaction.command.IndexTransactionApplier$LabelUpdateWork.apply(IndexTransactionApplier.java:139) ~[neo4j-kernel-2.2.3.jar:2.2.3]
... 42 common frames omitted
Suppressed: java.io.FileNotFoundException: /home/centos/neo4j-community-2.2.3/data/graph.db/schema/label/lucene/_179hv.fdt (Permission denied)
at java.io.RandomAccessFile.open(Native Method) ~[na:1.7.0_85]
at java.io.RandomAccessFile.<init>(RandomAccessFile.java:241) ~[na:1.7.0_85]
at org.apache.lucene.store.FSDirectory$FSIndexOutput.<init>(FSDirectory.java:441) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.store.FSDirectory.createOutput(FSDirectory.java:306) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.FieldsWriter.<init>(FieldsWriter.java:83) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.StoredFieldsWriter.initFieldsWriter(StoredFieldsWriter.java:64) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.StoredFieldsWriter.finishDocument(StoredFieldsWriter.java:107) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.StoredFieldsWriter$PerDoc.finish(StoredFieldsWriter.java:151) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.DocumentsWriter$WaitQueue.writeDocument(DocumentsWriter.java:1404) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.DocumentsWriter$WaitQueue.add(DocumentsWriter.java:1424) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.DocumentsWriter.finishDocument(DocumentsWriter.java:1043) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.DocumentsWriter.updateDocument(DocumentsWriter.java:772) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.IndexWriter.updateDocument(IndexWriter.java:2328) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.apache.lucene.index.IndexWriter.updateDocument(IndexWriter.java:2300) ~[lucene-core-3.6.2.jar:3.6.2 1423725 - rmuir - 2012-12-18 19:45:40]
at org.neo4j.kernel.api.impl.index.LuceneIndexWriter.updateDocument(LuceneIndexWriter.java:67) ~[neo4j-lucene-index-2.2.3.jar:2.2.3]
at org.neo4j.kernel.api.impl.index.TrackingLuceneIndexWriter.updateDocument(TrackingLuceneIndexWriter.java:55) ~[neo4j-lucene-index-2.2.3.jar:2.2.3]
at org.neo4j.kernel.api.impl.index.LuceneLabelScanStore.updateDocument(LuceneLabelScanStore.java:150) ~[neo4j-lucene-index-2.2.3.jar:2.2.3]
at org.neo4j.kernel.api.impl.index.LuceneLabelScanWriter.flush(LuceneLabelScanWriter.java:156) ~[neo4j-lucene-index-2.2.3.jar:2.2.3]
at org.neo4j.kernel.api.impl.index.LuceneLabelScanWriter.close(LuceneLabelScanWriter.java:87) ~[neo4j-lucene-index-2.2.3.jar:2.2.3]
at org.neo4j.kernel.impl.transaction.command.IndexTransactionApplier$LabelUpdateWork.apply(IndexTransactionApplier.java:141) ~[neo4j-kernel-2.2.3.jar:2.2.3]
... 42 common frames omitted
为什么会一次又一次地发生以下错误？虽然在重新安装带有数据库备份的Neo4j时，一段时间内工作正常。