From user-return-24541-apmail-cassandra-user-archive=cassandra.apache.org@cassandra.apache.org Mon Mar 5 10:45:06 2012 Return-Path: X-Original-To: apmail-cassandra-user-archive@www.apache.org Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 6CA4C9F69 for ; Mon, 5 Mar 2012 10:45:06 +0000 (UTC) Received: (qmail 46882 invoked by uid 500); 5 Mar 2012 10:45:04 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 46853 invoked by uid 500); 5 Mar 2012 10:45:04 -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 46840 invoked by uid 99); 5 Mar 2012 10:45:04 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 05 Mar 2012 10:45:04 +0000 X-ASF-Spam-Status: No, hits=2.2 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: local policy) Received: from [208.113.200.5] (HELO homiemail-a92.g.dreamhost.com) (208.113.200.5) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 05 Mar 2012 10:44:58 +0000 Received: from homiemail-a92.g.dreamhost.com (localhost [127.0.0.1]) by homiemail-a92.g.dreamhost.com (Postfix) with ESMTP id 9711F3DC05B for ; Mon, 5 Mar 2012 02:44:37 -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=vWjhrdlV0e fKh/xQZfHCLqa+RjUNKOkRXsl5SxCtoJwPX1erbQCkCOEyYl82FMVOq3KlIjTIiS 5NtZmL3EO0YDaTQD8F+RT2Guo6qSPQ5NK3KsyEH7uFO3c0VltxpddqRzhJIB0tEo r+ni5mZl3SlLLqglgZZidj68n5CGfw0is= 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=bOLZ9ZWVKeNwVLDA Z20tFZajXrA=; b=xjIpC1t0xl9JOCmpULq+B1vpxJh6INko920nrHT0L+2Aerh4 GJ5D73UBIuHr+MO24Ir2vLfLpt4iq6s9y/+35Mao8jDkGP5TBqMyHAegJBtOTNow rgh7SIwvodk+EImDrrt+sIF+n6656IwrqXCZ0SDQ6ZqvxoHx979j7HDJdr0= Received: from [172.16.1.3] (125-236-193-159.adsl.xtra.co.nz [125.236.193.159]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) (Authenticated sender: aaron@thelastpickle.com) by homiemail-a92.g.dreamhost.com (Postfix) with ESMTPSA id D37E83DC00B for ; Mon, 5 Mar 2012 02:44:36 -0800 (PST) From: aaron morton Mime-Version: 1.0 (Apple Message framework v1257) Content-Type: multipart/alternative; boundary="Apple-Mail=_FB16DACF-70CE-4849-AF1C-5EBB2D3F8F92" Subject: Re: Mutation Dropped Messages Date: Mon, 5 Mar 2012 23:44:33 +1300 In-Reply-To: To: user@cassandra.apache.org References: Message-Id: <802222A2-ECF8-42FA-8767-2B9BBAFEBEAD@thelastpickle.com> X-Mailer: Apple Mail (2.1257) X-Virus-Checked: Checked by ClamAV on apache.org --Apple-Mail=_FB16DACF-70CE-4849-AF1C-5EBB2D3F8F92 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 > 1. Which parameters to tune in the config files? =96 Especially = looking for heavy writes The node is overloaded. It may be because there are no enough nodes, or = the node is under temporary stress such as GC or repair.=20 If you have spare IO / CPU capacity you could increase the = current_writes to increase throughput on the write stage. You then need = to ensure the commit log and, to a lesser degree, the data volumes can = keep up.=20 > 2. What is the difference between TimedOutException and silently = dropping mutation messages while operating on a CL of QUORUM. TimedOutExceptions means CL nodes did not respond to the coordinator = before rpc_timeout. Dropping messages happens when a message is removed = from the queue in the a thread pool after rpc_timeout has occurred. it = is a feature of the architecture, and correct behaviour under stress.=20 Inconsistencies created by dropped messages are repaired via reads as = high CL, HH (in 1.+), Read Repair or Anti Entropy. Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 5/03/2012, at 11:32 PM, Tiwari, Dushyant wrote: > Hi All, > =20 > While benchmarking Cassandra I found =93Mutation Dropped=94 messages = in the logs. Now I know this is a good old question. It will be really = great if someone can provide a check list to recover when such a thing = happens. I am looking for answers of the following questions - > =20 > 1. Which parameters to tune in the config files? =96 Especially = looking for heavy writes > 2. What is the difference between TimedOutException and silently = dropping mutation messages while operating on a CL of QUORUM. > =20 > =20 > Regards, > Dushyant > NOTICE: Morgan Stanley is not acting as a municipal advisor and the = opinions or views contained herein are not intended to be, and do not = constitute, advice within the meaning of Section 975 of the Dodd-Frank = Wall Street Reform and Consumer Protection Act. If you have received = this communication in error, please destroy all electronic and paper = copies and notify the sender immediately. Mistransmission is not = intended to waive confidentiality or privilege. Morgan Stanley reserves = the right, to the extent permitted under applicable law, to monitor = electronic communications. This message is subject to terms available at = the following link: http://www.morganstanley.com/disclaimers. If you = cannot access these links, please notify us by reply message and we will = send the contents to you. By messaging with Morgan Stanley you consent = to the foregoing. --Apple-Mail=_FB16DACF-70CE-4849-AF1C-5EBB2D3F8F92 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252
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http://www.thelastpickle.com

On 5/03/2012, at 11:32 PM, Tiwari, Dushyant = wrote:

Hi All,
 
While benchmarking Cassandra I found =93Mutation Dropped=94 = messages in the logs.  Now I know this is a good old question. It = will be really great if someone can provide a check list to recover when = such a thing happens. I am looking for answers of the following = questions  -
 
1. Which = parameters to tune in the config files? =96 Especially looking for heavy = writes
2. What is the = difference between TimedOutException and silently dropping mutation = messages while operating on a CL of QUORUM.
 
 
Regards,

NOTICE: Morgan Stanley is not = acting as a municipal advisor and the opinions or views contained herein = are not intended to be, and do not constitute, advice within the meaning = of Section 975 of the Dodd-Frank Wall Street Reform and Consumer = Protection Act. <= /font>If you have received this = communication in error, please destroy all electronic and paper copies = and notify the sender immediately. Mistransmission is not intended to = waive confidentiality or privilege. Morgan Stanley reserves the right, = to the extent permitted under applicable law, to monitor electronic = communications. This message is subject to terms available at the = following link: http://www.morganstanley.com/disclaimers. If you cannot access these links, please = notify us by reply message and we will send the contents to you. By = messaging with Morgan Stanley you consent to the = foregoing.

= = --Apple-Mail=_FB16DACF-70CE-4849-AF1C-5EBB2D3F8F92--