[
https://issues.apache.org/jira/browse/HDFS-7715?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14360119#comment-14360119
]
jack liuquan commented on HDFS-7715:
------------------------------------
Hi Rashmi,
as you mentioned in your paper, Hitchhiker-XOR+ need the underlying RS code to
possess the all-XOR-parity property.
and the matrix 'generatorMatrixForParity' is the generator matrix of the
underlying RS code employed in HDFS-RAID.
I found the 'generatorMatrixForParity' not having the all-XOR-parity property.
Is that mean Hitchhiker-XOR+ can't been used for current HDFS-RAID?
ps:
I have tested the reconstruction of tenth unit data of Hitchhiker-XOR+ with the
test code in TestErasureCodes.java,
and found the result was not right. But the Hitchhiker-nonXOR's result was
right.
test Hitchhiker-XOR+ running logs:
=======stripe data=======
0:1,|0:2,|0:3,|0:4,|0:5,|0:6,|0:7,|0:8,|0:9,|0:10,|
0:1,|0:2,|0:3,|0:4,|0:5,|0:6,|0:7,|0:8,|0:9,|0:10,|
======parity data after encode=======
94,-74,44,6
94,-74,43,-55
=====readBufs=======
0:0,|0:0,|0:0,|0:6,|0:0,|0:0,|0:0,|0:0,|0:0,|0:0,|0:0,|0:0,|0:0,|0:0,|
0:94,|0:-74,|0:43,|0:0,|0:1,|0:2,|0:3,|0:4,|0:5,|0:6,|0:7,|0:8,|0:9,|0:0,|
=====writeBufs=======
0:-50,|0:0,|0:0,|0:0,|
0:10,|0:-74,|0:44,|0:-49,|
> Implement the Hitchhiker erasure coding algorithm
> -------------------------------------------------
>
> Key: HDFS-7715
> URL: https://issues.apache.org/jira/browse/HDFS-7715
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Zhe Zhang
> Assignee: jack liuquan
>
> [Hitchhiker |
> http://www.eecs.berkeley.edu/~nihar/publications/Hitchhiker_SIGCOMM14.pdf] is
> a new erasure coding algorithm developed as a research project at UC
> Berkeley. It has been shown to reduce network traffic and disk I/O by 25%-45%
> during data reconstruction. This JIRA aims to introduce Hitchhiker to the
> HDFS-EC framework, as one of the pluggable codec algorithms.
> The existing implementation is based on HDFS-RAID.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
