CODEWITHSUNDEEP
cassandracassandra-2.0
Prabhath
Prabhath

Reputation: 629

How does cassandra handle file system Partitions

My Situation: I have a server with multiple hard disks.

If i install cassandra(2.1.9) on the server and use all the hard disks. What happens if one hard disk goes down?

  1. Will it black list only that (Hard disk)partition and move the partitions(cassandra partitions) to other nodes or to the system partitions on same node.
  2. Will it treat as if the entire node went down.

Upvotes: 1

Views: 233

Answers (1)

Jim Meyer
Jim Meyer

Reputation: 9475

The behavior is configured in cassandra.yaml using the disk_failure_policy setting. See documentation here.

disk_failure_policy: (Default: stop) Sets how Cassandra responds to disk failure.
    Recommend settings are stop or best_effort.

die - Shut down gossip and Thrift and kill the JVM for any file system errors 
    or single SSTable errors, so the node can be replaced.

stop_paranoid - Shut down gossip and Thrift even for single SSTable errors.

stop - Shut down gossip and Thrift, leaving the node effectively dead,
    but available for inspection using JMX.

best_effort - Stop using the failed disk and respond to requests based on 
    the remaining available SSTables. This means you will see obsolete data 
    at consistency level of ONE.

ignore - Ignores fatal errors and lets the requests fail; all file system 
    errors are logged but otherwise ignored. Cassandra acts as in versions
    prior to 1.2.

You can find documentation on how to recover from a disk failure here. Cassandra will not automatically move data from a failed disk to the good disks. It requires manual intervention to correct the problem.

Upvotes: 2

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