File corruption when reading with fuse-dfs
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Key: HADOOP-4298
URL: https://issues.apache.org/jira/browse/HADOOP-4298
Project: Hadoop Core
Issue Type: Bug
Components: contrib/fuse-dfs
Affects Versions: 0.18.1
Environment: CentOs 4.6 final; kernel 2.6.9-67.ELsmp; FUSE 2.7.4;
hadoop 0.18.1; 64-bit
I hand-altered the fuse-dfs makefile to use 64-bit instead of the hardcoded
-m32.
Reporter: Brian Bockelman
Priority: Critical
Fix For: 0.18.1
I pulled a 5GB data file into Hadoop using the following command:
hadoop fs -put /scratch/886B9B3D-6A85-DD11-A9AB-000423D6CA6E.root
/user/brian/testfile
I have HDFS mounted in /mnt/hadoop using fuse-dfs.
However, when I try to md5sum the file in place (md5sum /mnt/hadoop) or copy
the file back to local disk using "cp" then md5sum it, the checksum is
incorrect.
When I pull the file using normal hadoop means (hadoop fs -get
/user/brian/testfile /scratch), the md5sum is correct.
When I repeat the test with a smaller file (512MB, on the theory that there is
a problem with some 2GB limit somewhere), the problem remains.
When I repeat the test, the md5sum is consistently wrong - i.e., some part of
the corruption is deterministic, and not the apparent fault of a bad disk.
CentOs 4.6 is, unfortunately, not the apparent culprit. When checking on
CentOs 5.x, I could recreate the corruption issue. The second node was also a
64-bit compile and CentOs 5.2 (`uname -r` returns 2.6.18-92.1.10.el5).
Thanks for looking into this,
Brian
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