Return-Path: Delivered-To: apmail-hadoop-common-commits-archive@www.apache.org Received: (qmail 61873 invoked from network); 18 Dec 2009 19:00:48 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.3) by minotaur.apache.org with SMTP; 18 Dec 2009 19:00:48 -0000 Received: (qmail 204 invoked by uid 500); 18 Dec 2009 19:00:48 -0000 Delivered-To: apmail-hadoop-common-commits-archive@hadoop.apache.org Received: (qmail 99989 invoked by uid 500); 18 Dec 2009 19:00:48 -0000 Mailing-List: contact common-commits-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: common-dev@hadoop.apache.org Delivered-To: mailing list common-commits@hadoop.apache.org Received: (qmail 99980 invoked by uid 500); 18 Dec 2009 19:00:48 -0000 Delivered-To: apmail-hadoop-core-commits@hadoop.apache.org Received: (qmail 99977 invoked by uid 99); 18 Dec 2009 19:00:48 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 18 Dec 2009 19:00:48 +0000 X-ASF-Spam-Status: No, hits=-2.6 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: apache.org Received: from [140.211.11.130] (HELO eos.apache.org) (140.211.11.130) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 18 Dec 2009 19:00:41 +0000 Received: from eos.apache.org (localhost [127.0.0.1]) by eos.apache.org (Postfix) with ESMTP id 3A6F817D14; Fri, 18 Dec 2009 19:00:21 +0000 (GMT) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Apache Wiki To: Apache Wiki Date: Fri, 18 Dec 2009 19:00:21 -0000 Message-ID: <20091218190021.11454.77106@eos.apache.org> Subject: =?utf-8?q?=5BHadoop_Wiki=5D_Update_of_=22Hbase/Troubleshooting=22_by_Andr?= =?utf-8?q?ewPurtell?= Dear Wiki user, You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for ch= ange notification. The "Hbase/Troubleshooting" page has been changed by AndrewPurtell. http://wiki.apache.org/hadoop/Hbase/Troubleshooting?action=3Ddiff&rev1=3D35= &rev2=3D36 -------------------------------------------------- = = <> - =3D=3D 13. Problem: Long client pauses under high load; or deadlock if us= ing transactional HBase (THBase)=3D=3D + =3D=3D 13. Problem: Long client pauses under high load; or deadlock if us= ing transactional HBase (THBase) =3D=3D * Under high load, some client operations take a long time; waiting appe= ars uneven * If using THBase, apparent deadlocks: for example, in thread dumps IPC = Server handlers are blocked in org.apache.hadoop.hbase.regionserver.tablein= dexed.IndexedRegion.updateIndex() - =3D=3D Causes =3D=3D + =3D=3D=3D Causes =3D=3D=3D * The default number of regionserver RPC handlers is insufficient. - =3D=3D Resolution =3D=3D + =3D=3D=3D Resolution =3D=3D=3D * Increase the value of "hbase.regionserver.handler.count" in hbase-site= .xml. The default is 10. Try 100. = = @@ -222, +222 @@ closing session 0x0 to sun.nio.ch.SelectionKeyImpl@656dc861 java.net.ConnectException: Connection refused }}} - =3D=3D Causes =3D=3D + =3D=3D=3D Causes =3D=3D=3D * Security group policy is blocking the Zookeeper port on a public addre= ss. - =3D=3D Resolution =3D=3D + =3D=3D=3D Resolution =3D=3D=3D * Use the internal EC2 host names when configuring the Zookeeper quorum = peer list. = = = <> =3D=3D 15. Problem: General operating environment issues -- zookeeper ses= sion timeouts, regionservers shutting down, etc =3D=3D - =3D=3D Causes =3D=3D + =3D=3D=3D Causes =3D=3D=3D Various. - =3D=3D Resolution =3D=3D + =3D=3D=3D Resolution =3D=3D=3D See the [[http://wiki.apache.org/hadoop/ZooKeeper/Troubleshooting ZooKeep= er Operating Environment Troubleshooting]] page. It has suggestions and to= ols for checking disk and networking performance; i.e. the operating enviro= nment your zookeeper and hbase are running in. ZooKeeper is the cluster's = "canary". It'll be the first to notice issues if any so making sure its ha= ppy is the short-cut to a humming cluster. = = <> =3D=3D 16. Problem: Scanner performance is low =3D=3D - =3D=3D Causes =3D=3D + =3D=3D=3D Causes =3D=3D=3D Default scanner caching (prefetching) is set to 1. The default is low bec= ause if a job takes too long processing, a scanner can time out, which caus= es unhappy jobs/people/emails. See item #10 above. - =3D=3D Resolution =3D=3D + =3D=3D=3D Resolution =3D=3D=3D * Increase the amount of prefetching on the scanner, to 10, or 100, or 1= 000, as appropriate for your workload: [[http://hadoop.apache.org/hbase/doc= s/current/api/org/apache/hadoop/hbase/client/HTable.html#scannerCaching|HTa= ble.scannerCaching]] * This change can be accomplished globally by setting the hbase.client.s= canner.caching property in hbase-site.xml to the desired value. = = <> =3D=3D 17. Problem: My shell or client application throws lots of scary e= xceptions during normal operation =3D=3D - =3D=3D Causes =3D=3D + =3D=3D=3D Causes =3D=3D=3D Since 0.20.0 the default log level for org.apache.hadoop.hbase.* is DEBUG. - =3D=3D Resolution =3D=3D + =3D=3D=3D Resolution =3D=3D=3D On your clients, edit $HBASE_HOME/conf/log4j.properties and change this: = {{{log4j.logger.org.apache.hadoop.hbase=3DDEBUG}}} to this: {{{log4j.logger.org.apache.hadoop.hbase=3DINFO}}}, or even {{{lo= g4j.logger.org.apache.hadoop.hbase=3DWARN}}} . =20