Hi Liang Did you mean set dfs.permissions to false?
Is that all I need to do to disable security feature? Cause It seems to me that without change dfs.block.local-path-access.user, dfs.permissions alone doesn't works. HBASE still fall back to go through datanode to read data. > > Hi Raymond, > > did you enable security feature in your cluster? there'll be no obvious > benefit > be found if so. > > Regards, > Liang > _______________________________________ > 发件人: Liu, Raymond [[email protected]] > 发送时间: 2013年2月16日 11:10 > 收件人: [email protected] > 主题: why my test result on dfs short circuit read is slower? > > Hi > > I tried to use short circuit read to improve my hbase cluster MR scan > performance. > > I have the following setting in hdfs-site.xml > > dfs.client.read.shortcircuit set to true > dfs.block.local-path-access.user set to MR job runner. > > The cluster is 1+4 node and each data node have 16cpu/4HDD, with > all hbase table major compact thus all data is local. > I have hoped that the short circuit read will improve the > performance. > > While the test result is that with short circuit read enabled, the > performance actually dropped 10-15%. Say scan a 50G table cost around 100s > instead of 90s. > > My hadoop version is 1.1.1, any idea on this? Thx! > > Best Regards, > Raymond Liu
