Apache Cassandra启动失败：FSWriteError（...）操作不允许

Question

为了测试目的，我设置了一个带有两个节点的小型Cassandra集群。在第二个节点上启动卡桑德拉我得到这个异常：

INFO [main] 2014-11-05 11:49:10,253 AutoSavingCache.java:123 - reading saved cache /var/lib/cassandra/saved_caches/system-local-7ad54392bcdd35a684174e047860b377-KeyCache-b.db 
ERROR [main] 2014-11-05 11:49:10,855 CassandraDaemon.java:460 - Exception encountered during startup 
org.apache.cassandra.io.FSWriteError: java.nio.file.FileSystemException: /var/lib/cassandra/data/system/compactions_in_progress-55080ab05d9c388690a4acb25fe1f77b/snapshots/1415184550829-compactions_in_progress/system-compactions_in_progress-ka-2-Summary.db -> /var/lib/cassandra/data/system/compactions_in_progress-55080ab05d9c388690a4acb25fe1f77b/system-compactions_in_progress-ka-2-Summary.db: Die Operation ist nicht erlaubt 
    at org.apache.cassandra.io.util.FileUtils.createHardLink(FileUtils.java:98) ~[apache-cassandra-2.1.1.jar:2.1.1] 
    at org.apache.cassandra.io.sstable.SSTableReader.createLinks(SSTableReader.java:1728) ~[apache-cassandra-2.1.1.jar:2.1.1] 
    at org.apache.cassandra.db.ColumnFamilyStore.snapshotWithoutFlush(ColumnFamilyStore.java:2158) ~[apache-cassandra-2.1.1.jar:2.1.1] 
    at org.apache.cassandra.db.ColumnFamilyStore.snapshot(ColumnFamilyStore.java:2215) ~[apache-cassandra-2.1.1.jar:2.1.1] 
    at org.apache.cassandra.db.ColumnFamilyStore.snapshot(ColumnFamilyStore.java:2209) ~[apache-cassandra-2.1.1.jar:2.1.1] 
    at org.apache.cassandra.db.ColumnFamilyStore$10.run(ColumnFamilyStore.java:2449) ~[apache-cassandra-2.1.1.jar:2.1.1] 
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) ~[na:1.7.0_65] 
    at org.apache.cassandra.db.ColumnFamilyStore.runWithCompactionsDisabled(ColumnFamilyStore.java:2515) ~[apache-cassandra-2.1.1.jar:2.1.1] 
    at org.apache.cassandra.db.ColumnFamilyStore.truncateBlocking(ColumnFamilyStore.java:2462) ~[apache-cassandra-2.1.1.jar:2.1.1] 
    at org.apache.cassandra.db.SystemKeyspace.discardCompactionsInProgress(SystemKeyspace.java:267) ~[apache-cassandra-2.1.1.jar:2.1.1] 
    at org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:234) [apache-cassandra-2.1.1.jar:2.1.1] 
    at org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:443) [apache-cassandra-2.1.1.jar:2.1.1] 
    at org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:532) [apache-cassandra-2.1.1.jar:2.1.1] 
Caused by: java.nio.file.FileSystemException: /var/lib/cassandra/data/system/compactions_in_progress-55080ab05d9c388690a4acb25fe1f77b/snapshots/1415184550829-compactions_in_progress/system-compactions_in_progress-ka-2-Summary.db -> /var/lib/cassandra/data/system/compactions_in_progress-55080ab05d9c388690a4acb25fe1f77b/system-compactions_in_progress-ka-2-Summary.db: Die Operation ist nicht erlaubt 
    at sun.nio.fs.UnixException.translateToIOException(UnixException.java:91) ~[na:1.7.0_65] 
    at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102) ~[na:1.7.0_65] 
    at sun.nio.fs.UnixFileSystemProvider.createLink(UnixFileSystemProvider.java:475) ~[na:1.7.0_65] 
    at java.nio.file.Files.createLink(Files.java:1039) ~[na:1.7.0_65] 
    at org.apache.cassandra.io.util.FileUtils.createHardLink(FileUtils.java:94) ~[apache-cassandra-2.1.1.jar:2.1.1] 
    ... 12 common frames omitted 

我知道，通过删除在/ var/lib中/卡桑德拉/数据/异常的keyspaces不再被抛出卡桑德拉启动。但必须有一个更清洁的解决方案。

Answer 1

大多数情况下，当您通常使用名为cassandra的特殊弱势用户启动cassandra时，会发生这种情况。但是最后一次以root身份启动cassandra。

现在您拥有一些由root拥有的文件/文件夹，cassandra用户无法访问它们。

为了解决这个问题，你只需要以root身份运行（如果卡桑德拉是弱势用户）：
chown -R cassandra:cassandra /var/lib/cassandra/data/*

这样卡桑德拉应正常启动后。