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https://issues.apache.org/jira/browse/HDFS-7285?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14189366#comment-14189366
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Zhe Zhang commented on HDFS-7285:
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A meeting has been scheduled:
* When: Friday Oct. 31st 10am~12pm
* Where: Cloudera Headquarter, 1001 Page Mill Road, Palo Alto. Both the lobby
(for guests check-in) and the meeting room (Hadoop) are in building #2
* URL:
https://cloudera.webex.com/cloudera/j.php?MTID=me26394d0a3559c7a9498f18ad7de8962
* Call-in: 1-650-479-3208 (US/Canada) with access code: 290 472 605.
Please drop me a note (zhezh...@cloudera.com) if you prefer a different time.
Thanks [~drankye] for the suggestion. The interface of the erasure coding
feature potentially has a close relationship with HSM (HDFS-2832) and archival
storage (HDFS-6584). We'll make sure to cover this topic in the meeting and
share the summary here.
> Erasure Coding Support inside HDFS
> ----------------------------------
>
> Key: HDFS-7285
> URL: https://issues.apache.org/jira/browse/HDFS-7285
> Project: Hadoop HDFS
> Issue Type: New Feature
> Reporter: Weihua Jiang
> Assignee: Zhe Zhang
> Attachments: HDFSErasureCodingDesign-20141028.pdf
>
>
> Erasure Coding (EC) can greatly reduce the storage overhead without sacrifice
> of data reliability, comparing to the existing HDFS 3-replica approach. For
> example, if we use a 10+4 Reed Solomon coding, we can allow loss of 4 blocks,
> with storage overhead only being 40%. This makes EC a quite attractive
> alternative for big data storage, particularly for cold data.
> Facebook had a related open source project called HDFS-RAID. It used to be
> one of the contribute packages in HDFS but had been removed since Hadoop 2.0
> for maintain reason. The drawbacks are: 1) it is on top of HDFS and depends
> on MapReduce to do encoding and decoding tasks; 2) it can only be used for
> cold files that are intended not to be appended anymore; 3) the pure Java EC
> coding implementation is extremely slow in practical use. Due to these, it
> might not be a good idea to just bring HDFS-RAID back.
> We (Intel and Cloudera) are working on a design to build EC into HDFS that
> gets rid of any external dependencies, makes it self-contained and
> independently maintained. This design lays the EC feature on the storage type
> support and considers compatible with existing HDFS features like caching,
> snapshot, encryption, high availability and etc. This design will also
> support different EC coding schemes, implementations and policies for
> different deployment scenarios. By utilizing advanced libraries (e.g. Intel
> ISA-L library), an implementation can greatly improve the performance of EC
> encoding/decoding and makes the EC solution even more attractive. We will
> post the design document soon.
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