J-D's presentation can give you some idea about the speedup: http://files.meetup.com/1350427/hug_ebay_jdcryans.pdf
Thanks On Sun, Jan 27, 2013 at 2:38 PM, Jean-Marc Spaggiari < [email protected]> wrote: > Does this have a significant increase on HBase performances? And what > are the "risks" associated with short-circuit activation (if any)? No > risks of corrupting data? > > Can this be activated after tables are already populated? > > JM > > 2013/1/27, Ted <[email protected]>: > > For hbase internal checksum, it is not in hbase 0.92.x release. > > > > Please use 0.94.2 or newer release. > > > > Thanks > > > > On Jan 27, 2013, at 2:29 PM, David Koch <[email protected]> wrote: > > > >> Hello, > >> > >> I read about "short circuit reads" in the HBase documentation's > >> performance > >> section[1] and was wondering what people's experiences were using this > in > >> a > >> production setting. > >> > >> Also, > >> > >> 1. Since only one dedicated user can take advantage of the feature do > you > >> launch all jobs as this user? > >> 2. Can dfs.client.read.shortcircuit be set to false for jobs wich are > not > >> launched by the short-circuit user in order to avoid exceptions? In > other > >> words - can this setting be overriden by the client configuration's > >> hbase-site.xml? > >> 3. In the same context, it is suggested to enable HBase internal > >> checksums[2]. Is this a feature which can be enabled in HBase 0.92.1 > >> which > >> is part of the Cloudera 4.1.x release? > >> > >> Thank you, > >> > >> /David > >> > >> [1] http://hbase.apache.org/book/perf.hdfs.html#ftn.d2145e7370 > >> [2] https://issues.apache.org/jira/browse/HBASE-5074 > > >
