Ewan Higgs created HDFS-13186: --------------------------------- Summary: Multipart Multinode uploader API + Implementations Key: HDFS-13186 URL: https://issues.apache.org/jira/browse/HDFS-13186 Project: Hadoop HDFS Issue Type: Sub-task Reporter: Ewan Higgs
To write files in parallel to an external storage system as in HDFS-12090, there are two approaches: # Naive approach: use a single datanode per file that copies blocks locally as it streams data to the external service. This requires a copy for each block inside the HDFS system and then a copy for the block to be sent to the external system. # Better approach: Single point (e.g. Namenode or SPS style external client) and Datanodes coordinate in a multipart - multinode upload. This system needs to work with multiple back ends and needs to coordinate across the network. So we propose an API that resembles the following: {code:java} public UploadHandle multipartInit(Path filePath) throws IOException; public PartHandle multipartPutPart(InputStream inputStream, int partNumber, UploadHandle uploadId) throws IOException; public void multipartComplete(Path filePath, List<Pair<Integer, PartHandle>> handles, UploadHandle multipartUploadId) throws IOException;{code} Here, UploadHandle and PartHandle are opaque handlers in the vein of PathHandle so they can be serialized and deserialized in hadoop-hdfs project without knowledge of how to deserialize e.g. S3A's version of a UpoadHandle and PartHandle. In an object store such as S3A, the implementation is straight forward. In the case of writing multipart/multinode to HDFS, we can write each block as a file part. The complete call will perform a concat on the blocks. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org