Hello, Thank you for your reply, I checked the HDFS log for error messages that are indicative of "xciever" problems but could not find any. The settings suggested here: http://blog.cloudera.com/blog/2012/03/hbase-hadoop-xceivers/have been applied on our cluster.
I did a grep "File does not exist: /hbase/<table_name>/" /var/log/hadoop-hdfs/hadoop-cmf-hdfs1-NAMENODE-big* | wc on the namenode logs and there millions of such lines for one table only. The count is 0 for all other tables - even though they may be reported as inconsistent by hbchk. It seems like this is less of a performance issue but rather some stale "where to find what data" problem - possibly related to Zookeeper? I remember there being some kind of procedure for clearing ZK even though I cannot recall the steps involved. Any further help would be appreciated, Thanks, /David On Sun, Feb 10, 2013 at 2:24 AM, Dhaval Shah <[email protected]>wrote: > > It seems like you need to increase the limit on the number of xceivers on > the hdfs config looking at your error messages. > > > ------------------------------ > On Sun 10 Feb, 2013 6:37 AM IST David Koch wrote: > > >Hello, > > > >As of lately, we have been having issues with Region Servers crashing in > >our cluster. This happens while running Map/Reduce jobs over HBase tables > >in particular but also spontaneously when the cluster is seemingly idle. > > > >Restarting the Region Servers or even HBase entirely as well as HDFS and > >Map/Reduce services does not fix the problem and jobs will fail during the > >next attempt citing "Region not served" exceptions. It is not always the > >same nodes that crash. > > > >The log data during the minutes leading up to the crash contain many "File > >does not exist /hbase/<table_name>/..." error messages which change to > "Too > >many open files" messages, finally, there are a few "Failed to renew lease > >for DFSClient" messages followed by several "FATAL" messages about HLog > not > >being able to synch and immediately afterwards a terminal "ABORTING region > >server". > > > >You can find an extract of a Region Server log here: > >http://pastebin.com/G39LQyQT. > > > >Running "hbase hbck" reveals inconsistencies in some tables, but > attempting > >a repair with "hbase hbck -repair" stalls due to some regions being in > >transition, see here: http://pastebin.com/JAbcQ4cc. > > > >The setup contains 30 machines, 26GB RAM each, the services are managed > >using CDH4, so HBase version is 0.92.x. We did not tweak any of the > default > >configuration settings, however table scans are done with sensible > >scan/batch/filter settings. > > > >Data intake is about 100GB/day which are added at a time when no > Map/Reduce > >jobs are running. Tables have between 100 * 10^6 and 2 * 10^9 rows, with > an > >average of 10 KVs, about 1kb each. Very few rows exceed 10^6 KV. > > > >What can we do to fix these issues? Are they symptomic of a mal-configured > >setup or some critical threshold level being reached? The cluster used to > >be stable. > > > >Thank you, > > > >/David > >
