[ACCUMULO-3727] FileNotFoundException on failed/data during recovery

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Cannot Reproduce
• Affects Version/s: 1.5.2
• Component/s: tserver
• Assignee: Unassigned
• Reporter: William Slacum
• Created: 14/Apr/15 19:17
• Updated: 19/Apr/19 01:08
• Resolved: 16/Apr/19 19:20

Description

Over night there was a mass failure of Accumulo (most likely due to too many mappers for a job). After restarting Accumulo, one of the metadata tablets failed to load. There was a log message showing a `FileNotFoundException` on the file `hdfs:///accumulo/recovery/<log id>/failed/data`. Removing the `<log id>` directory from HDFS seemed to unclog the jam and things came back (though potentially with data loss).

I wanted to investigate why somewhere in the plumbing of `TabletServer`, `TabletServerLogger`, and `SortedLogRecovery`, an attempt was made to use the `failure` file.

I see in `SortedLogRecovery#sort` where the marker file gets created:

public void sort(String name, Path srcPath, String destPath) {
...
      } catch (Throwable t) {
        try {
          // parent dir may not exist
          fs.mkdirs(new Path(destPath));
          fs.create(new Path(destPath, "failed")).close();
        } catch (IOException e) {
          log.error("Error creating failed flag file " + name, e);
        }
        log.error(t, t);
      } finally {
...

I have not stepped out to figure out where/why the `failed` files gets included in the list of recovered data dir.