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Xiaoyu Yao commented on HDFS-6934: ---------------------------------- Thanks [~cnauroth] for working on this. The fix looks good to me. Below are some of my comments: 1. FSOutputSummer.java If FSOutputSummer#getChecksumSize() is added to reduce individual call sum.getChecksumSize() in FSOutputSummer, there are still three Sum.getChecksumSize() calls that can be replaced with getChecksumSize(). 2. DataChecksum.java NIT: Can you add spaces between operators of * and + in DataChecksum#getChecksumSize(). 3. BlockReceiver.java If you put Line 582~583 before Line 574, you can use {code} If (shouldNotWriteChecksum) {code} instead of duplicating the same logic. 4. DFSInputStream.java Line 954: This can be moved out of the loop StorageType[] storageTypes = block.getStorageTypes(); Line 955: Can you add comment on the relationship between index of nodes (i) to the storage type selection if (storageTypes != null && i < storageTypes.length) { storageType = storageTypes[i]; } 5. TestLazyPersistFiles.java We have a separate test class for SCR related tests in TestScrLazyPersistFiles.java so that the temporary domain socket does not need to be created for non-SCR cases. Can put the new SCR cases there? I notice the test timeout attribute is removed. Is there a particular reason for that? DFS_DATANODE_RAM_DISK_LOW_WATERMARK_REPLICAS has been changed to DFS_DATANODE_RAM_DISK_LOW_WATERMARK_BYTES by HDFS-6988, can you sync with the trunk and update the patch? > Move checksum computation off the hot path when writing to RAM disk > ------------------------------------------------------------------- > > Key: HDFS-6934 > URL: https://issues.apache.org/jira/browse/HDFS-6934 > Project: Hadoop HDFS > Issue Type: Sub-task > Components: datanode > Reporter: Arpit Agarwal > Assignee: Chris Nauroth > Attachments: HDFS-6934.3.patch, h6934_20141003b.patch, > h6934_20141005.patch > > > Since local RAM is considered reliable we can avoid writing checksums on the > hot path when replicas are being written to a local RAM disk. > The checksum can be computed by the lazy writer when moving replicas to disk. -- This message was sent by Atlassian JIRA (v6.3.4#6332)