• Type: New Feature New Feature
    • Status: Resolved
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 0.8.1
    • Component/s: None
    • Labels:


      It still isn't feasible to run without an application level fsync policy. This is a problem as fsync locks the file and tuning such a policy so that the flushes aren't so frequent that seeks reduce throughput, yet not so infrequent that the fsync is writing so much data that there is a noticable jump in latency is very challenging.

      The remaining problem is the way that log recovery works. Our current policy is that if a clean shutdown occurs we do no recovery. If an unclean shutdown occurs we recovery the last segment of all logs. To make this correct we need to ensure that each segment is fsync'd before we create a new segment. Hence the fsync during roll.

      Obviously if the fsync during roll is the only time fsync occurs then it will potentially write out the entire segment which for a 1GB segment at 50mb/sec might take many seconds. The goal of this JIRA is to eliminate this and make it possible to run with no application-level fsyncs at all, depending entirely on replication and background writeback for durability.

      1. KAFKA-615-v1.patch
        51 kB
        Jay Kreps
      2. KAFKA-615-v2.patch
        60 kB
        Jay Kreps
      3. KAFKA-615-v3.patch
        61 kB
        Jay Kreps
      4. KAFKA-615-v4.patch
        61 kB
        Jay Kreps
      5. KAFKA-615-v5.patch
        62 kB
        Jay Kreps
      6. KAFKA-615-v6.patch
        62 kB
        Jay Kreps
      7. KAFKA-615-v7.patch
        62 kB
        Jay Kreps
      8. KAFKA-615-v8.patch
        62 kB
        Jay Kreps


        No work has yet been logged on this issue.


          • Assignee:
            Jay Kreps
            Jay Kreps
          • Votes:
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            • Created: