Hi,
WRT to “hbase-site.xml: Change hbase.regionserver.region.split.policy to org.apache.hadoop.hbase.regionserver.ConstantSizeRegionSplitPolicy”, I would imagine by now with the replies to your “Disable HBase Region Rebalancing” e-mail you can see how these two topics are related? Namely, if you don’t want regions to be split or move unexpectedly due to transaction considerations then using the default HBase policy of IncreasingToUpperBoundRegionSplitPolicy is even less desirable than the ConstantSizeRegionSplitPolicy because the former will be more aggressive in splitting regions from the beginning. At least with the latter policy and a sufficiently large file size you can ensure a region won’t split until your maintenance window. Even after the recommendation for the HBase Region Rebalancing is relaxed I’m not sure that recommending ConstantSizeRegionSplitPolicy won’t remain the better option. Granted this is an example of Trafodion changing an HBase default but reading the HBase JIRA and various web pages there’s nothing that makes me think IncreasingToUpperBoundRegionSplitPolicy is inherently superior to ConstantSizeRegionSplitPolicy without knowledge about the application. The problem with knobs is you have to have a default setting even if it’s “off”. In this case there is no “off” and I could argue that for most Trafodion users the ConstantSizeRegionSplitPolicy is the “safer” default because it can be confusing when you set the region size to 10GB only to have a region split happen after two memstore flushes of 128 MB using IncreasingToUpperBoundRegionSplitPolicy. --Dennis From: Gunnar Tapper [mailto:[email protected]] Sent: Monday, February 08, 2016 3:55 PM To: [email protected] Subject: Re: Trafodion environment changes Also, how relevant is this page: https://cwiki.apache.org/confluence/display/TRAFODION/Configuration It does not match what I find in the 1.3 installer. On Mon, Feb 8, 2016 at 2:37 PM, Gunnar Tapper <[email protected] <mailto:[email protected]> > wrote: Hi, I'm trying to understand the purpose of the different environmental changes that are required during Trafodion install to help administrators understand what needs to happen when installing Trafodion onto their Hadoop/HDFS/HBase environment. Think "what's the purpose of this configuration change", "what it this directory/file/jar/etc used for", and so on ZOOKEEPER * zoo.cfg: Change maxClientCnxns to 0. HDFS * Create /hbase-staging, change owner to HBase Administrator. * Create /bulkload, change owner to Trafodion. * Create /apps/hbase/data/archive, change owner to hbase:hbase (Cloudera) or hbase:hdfs (Hortonworks), give the trafodion RWX access, set default user to trafodion, and setaflc to RWX. HBASE * Install Trafodion utility jar into /usr/lib/hbase/lib (and other directories): what functions does this jar provide? * hbase-site.xml: Change hbase.coprocessor.region.classes to a list of classes. (It'd be good give a short description of each class.) * hbase-site.xml: Change hbase.hregion.impl to org.apache.hadoop.hbase.regionserver.transactional.TransactionalRegion * hbase-site.xml: Change hbase.regionserver.region.split.policy to org.apache.hadoop.hbase.regionserver.ConstantSizeRegionSplitPolicy -- Thanks, Gunnar If you think you can you can, if you think you can't you're right. -- Thanks, Gunnar If you think you can you can, if you think you can't you're right.
