Return-Path: Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: (qmail 38830 invoked from network); 14 Dec 2010 08:46:13 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 14 Dec 2010 08:46:13 -0000 Received: (qmail 2323 invoked by uid 500); 14 Dec 2010 08:46:11 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 2119 invoked by uid 500); 14 Dec 2010 08:46:11 -0000 Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@cassandra.apache.org Delivered-To: mailing list user@cassandra.apache.org Received: (qmail 2111 invoked by uid 99); 14 Dec 2010 08:46:11 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 14 Dec 2010 08:46:11 +0000 X-ASF-Spam-Status: No, hits=2.2 required=10.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: local policy) Received: from [208.113.200.5] (HELO homiemail-a42.g.dreamhost.com) (208.113.200.5) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 14 Dec 2010 08:46:03 +0000 Received: from homiemail-a42.g.dreamhost.com (localhost [127.0.0.1]) by homiemail-a42.g.dreamhost.com (Postfix) with ESMTP id 1E32968C065 for ; Tue, 14 Dec 2010 00:45:39 -0800 (PST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=thelastpickle.com; h=from :mime-version:content-type:subject:date:in-reply-to:to :references:message-id; q=dns; s=thelastpickle.com; b=rrZfLnRj1t 4Jp1VlfZymTteCeZ/aToQRBMmO2gr9YiZ9jng0DGVseX00WpDIonX/o7E9M3wjEO nPrPlhf6miuLEQG+/vMxSWaRbQPsOLNMRxMPZirjy4lCiSsMzDDHljzmLqMzgQnf gLxlos+BfgWIhtKbRcby59kg5aoN4eGq0= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=thelastpickle.com; h=from :mime-version:content-type:subject:date:in-reply-to:to :references:message-id; s=thelastpickle.com; bh=elziLOCs+SE4HPz+ ZQqxxOrHfNs=; b=i4SrYokcVeoJ2Di6NOuHiM6YCaYidev5Qxu1csKkgDm7zWl4 9NlN0Rg3Tv2VYPccXNtMHi1X/dYhKSD/bNBNv6JaP222nBQhNCJ9Mp6rwvK+SXQi GpQ77X0ByXtooo4kweu2lhP8/NdBz9+Wxl1DuGGgzHzGWLvOuFIXAR1iN4Y= Received: from [10.0.1.155] (121-73-157-230.cable.telstraclear.net [121.73.157.230]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) (Authenticated sender: aaron@thelastpickle.com) by homiemail-a42.g.dreamhost.com (Postfix) with ESMTPSA id 320CD68C05D for ; Tue, 14 Dec 2010 00:45:38 -0800 (PST) From: aaron morton Mime-Version: 1.0 (Apple Message framework v1082) Content-Type: multipart/alternative; boundary=Apple-Mail-2-476521712 Subject: Re: Unavailable exception with CL.ANY Date: Tue, 14 Dec 2010 21:45:34 +1300 In-Reply-To: <6FE2CF8E1CA397409647FA315E4411034462788EB7@VMBX124.ihostexchange.net> To: user@cassandra.apache.org References: <6FE2CF8E1CA397409647FA315E4411034462788EB7@VMBX124.ihostexchange.net> Message-Id: X-Mailer: Apple Mail (2.1082) X-Virus-Checked: Checked by ClamAV on apache.org --Apple-Mail-2-476521712 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 First thing you are going to need is some log messages. =46rom the = machine the client was connected to when it returned the = UnavailableException. At CL ANY even Hinted Handoff counts towards meeting the CL for a write = http://wiki.apache.org/cassandra/HintedHandoff . So as long as the = client can connect to a node in the cluster the write should be = accepted. But there could still be reasons why the HH could not be = recorded, the logs should help sort it out though. For a read, with RF 2 and 3 nodes down there may be an entire section of = the distributed hash table will be unavailable. So any read for a key = that is replicated on 2 of the 3 down nodes will fail. I would advise = getting those nodes up asap. Keys in all CF's are distributed around the cluster according to the = partitioner, replication strategy and initial tokens. If you are using = the Random Partitioner, Simple Replication Strategy and set evenly = spaced initial tokens then keys will be evenly spaced around the = cluster.=20 Hope that helps Aaron On 14 Dec 2010, at 21:12, Rajat Chopra wrote: > Hi! > I have a 16 node cluster with two keyspaces and several column = families within each, all with RF=3D2. > All the reads/writes work with all column families but only one of = them gives me an unavailable exception, even with CL.ANY consistency. = The nodetool ring shows that three of the nodes of the cluster are down = (they have their disk full because Cassandra runs out of memory and = leaves humongous hprof files). > =20 > Anyhow, my question is this =96 is the unavailable exception being = thrown because that particular column family (with its replica) happened = to be stored in the three nodes that were down? > Is there a way to see what keys/cfs are stored in which node(s) of the = cluster? > =20 > Thanks, > Rajat > =20 --Apple-Mail-2-476521712 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 First thing you are going to need is some log = messages. =46rom the machine the client was connected to when it = returned the UnavailableException.

At CL ANY even = Hinted Handoff counts towards meeting the CL for a write http://wiki.apache= .org/cassandra/HintedHandoff . So as long as the client can connect = to a node in the cluster the write should be accepted. But there could = still be reasons why the HH could not be recorded, the logs should help = sort it out though.

For a read, with RF 2 and 3 = nodes down there may be an entire section of the distributed hash table = will be unavailable. So any read for a key that is replicated on 2 of = the 3 down nodes will fail. I would advise getting those nodes up = asap.

Keys in all CF's are distributed around = the cluster according to the partitioner, replication strategy and = initial tokens. If you are using the Random Partitioner, Simple = Replication Strategy and set evenly spaced initial tokens then keys will = be evenly spaced around the cluster. 

Hope = that helps
Aaron

On 14 Dec = 2010, at 21:12, Rajat Chopra wrote:

Hi!
Anyhow, my question is this =96 is = the unavailable exception being thrown because that particular column = family (with its replica) happened to be stored in the three nodes that = were down?
Is there a way to see what keys/cfs = are stored in which node(s) of the cluster?
Thanks,