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Arpit Agarwal commented on HDFS-6702: ------------------------------------- bq. If we choose (a) then the index of targets and targetStorageTypes won't be matched in the receiver side since targets[1..n-1] becomes targets[0..n-2] and targetStorageTypes[0..n-1] remains targetStorageTypes[0..n-1], i.e. targetStorageTypes[0] is for the first DN, targetStorageTypes[1] is for the second DN and so on but targets[0] is for the second DN, targets[1] is for the third DN and so on. Okay I got it, this trick avoids special case code in {{writeBlock}}. Would you consider adding a short comment explaining this? bq. It is an two-dimensional array, which is similar to targetStorageUuids or targets in BlockCommandProto. Got it thanks. +1 > DFSClient should create blocks using StorageType > ------------------------------------------------- > > Key: HDFS-6702 > URL: https://issues.apache.org/jira/browse/HDFS-6702 > Project: Hadoop HDFS > Issue Type: Bug > Components: datanode, hdfs-client > Reporter: Tsz Wo Nicholas Sze > Assignee: Tsz Wo Nicholas Sze > Attachments: h6702_20140719.patch, h6702_20140721.patch, > h6702_20140721b.patch > > > When DFSClient asks NN for a new block (via addBlock), NN returns a > LocatedBlock with storage type information. However, DFSClient does not use > StorageType to create blocks with DN. As a result, the block replicas could > possibly be created with a different storage type. -- This message was sent by Atlassian JIRA (v6.2#6252)