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 E353ACA7A for ; Thu, 24 May 2012 10:00:46 +0000 (UTC) Received: (qmail 27581 invoked by uid 500); 24 May 2012 10:00:44 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 27558 invoked by uid 500); 24 May 2012 10:00:44 -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 27541 invoked by uid 99); 24 May 2012 10:00:44 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 24 May 2012 10:00:44 +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-a94.g.dreamhost.com) (208.113.200.5) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 24 May 2012 10:00:39 +0000 Received: from homiemail-a94.g.dreamhost.com (localhost [127.0.0.1]) by homiemail-a94.g.dreamhost.com (Postfix) with ESMTP id 54A5E38A059 for ; Thu, 24 May 2012 03:00:18 -0700 (PDT) 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=LW+w4vT8gL t3aKMWhY4OVbYxuyz8JGU91N5S4hGdWCgsla06kc7qF40VF4PIU7yjKsdPfmj3mz Nx8cXDmpefEZL1WHUBQg8XxkIUJkKW1oZJtjh7MUADqPyQGVFdoY15HBrvTEV773 bdGIdLopdpIF1yHj4DeEV5I3VpEgiQeCE= 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=aYBqtisvyPY3nv40 NWUfOXU3XUk=; b=pluWLBSaTvjlyLU/jpyzBdD7acPHPkhafPlbZDxBwJlP5W77 /EHFDqBkZAQl2IkGQv572RWDO+SWfIjQPYU2M4pSyQGK5vUSEznQqlHX6IJJlovq 6I4pMFhL+VlbWbdRM1+0ZrllX/Ma2eujBQ2R47kruWBGEta12UMdnEFIj/s= Received: from [172.16.1.4] (unknown [203.86.207.101]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) (Authenticated sender: aaron@thelastpickle.com) by homiemail-a94.g.dreamhost.com (Postfix) with ESMTPSA id 98DCF38A00C for ; Thu, 24 May 2012 03:00:17 -0700 (PDT) From: aaron morton Mime-Version: 1.0 (Apple Message framework v1257) Content-Type: multipart/alternative; boundary="Apple-Mail=_173EE989-866E-499A-9338-3DD77497B9C6" Subject: Re: Replication factor Date: Thu, 24 May 2012 22:00:12 +1200 In-Reply-To: <2C85E14562B39345BCCAD90B8E7955C914692F@DKEXC002.adform.com> To: user@cassandra.apache.org References: <5465E653-8578-42EF-A849-360610DC11DB@thelastpickle.com> <2C85E14562B39345BCCAD90B8E7955C913E4B4@DKEXC002.adform.com> <2C85E14562B39345BCCAD90B8E7955C914692F@DKEXC002.adform.com> Message-Id: <59E65970-9699-4517-BF7D-3E1B6E8007A4@thelastpickle.com> X-Mailer: Apple Mail (2.1257) X-Virus-Checked: Checked by ClamAV on apache.org --Apple-Mail=_173EE989-866E-499A-9338-3DD77497B9C6 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 Your experience is when using CL ONE the Dynamic Snitch is moving local = reads off to other nodes and this is causing spikes in read latency ?=20 Did you notice what was happening on the node for the DS to think it was = so slow ? Was compaction or repair going on ?=20 =20 Have you played with the badness threshold = https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#L472 = ?=20 Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 24/05/2012, at 5:28 PM, Viktor Jevdokimov wrote: > Depends on use case. For ours we have another experience and = statistics, when turning dynamic snitch off makes overall latency and = spikes much, much lower. > =20 > =20 >=20 >=20 > Best regards / Pagarbiai > Viktor Jevdokimov > Senior Developer >=20 > Email: Viktor.Jevdokimov@adform.com > Phone: +370 5 212 3063, Fax +370 5 261 0453 > J. Jasinskio 16C, LT-01112 Vilnius, Lithuania > Follow us on Twitter: @adforminsider > What is Adform: watch this short video > >=20 > Disclaimer: The information contained in this message and attachments = is intended solely for the attention and use of the named addressee and = may be confidential. If you are not the intended recipient, you are = reminded that the information remains the property of the sender. You = must not use, disclose, distribute, copy, print or rely on this e-mail. = If you have received this message in error, please contact the sender = immediately and irrevocably delete this message and any copies. >=20 > From: Brandon Williams [mailto:driftx@gmail.com]=20 > Sent: Thursday, May 24, 2012 02:35 > To: user@cassandra.apache.org > Subject: Re: Replication factor > =20 > On Wed, May 23, 2012 at 5:51 AM, Viktor Jevdokimov = wrote: > > When RF =3D=3D number of nodes, and you read at CL ONE you will = always be reading locally. > =93always be reading locally=94 =96 only if Dynamic Snitch is =93off=94.= With dynamic snitch =93on=94 request may be redirected to other node, = which may introduce latency spikes. > =20 > Actually it's preventing spikes, since if it won't read locally that = means the local replica is in worse shape than the rest (compacting, = repairing, etc.) > =20 > -Brandon=20 --Apple-Mail=_173EE989-866E-499A-9338-3DD77497B9C6 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252
Your experience is when using CL ONE the = Dynamic Snitch is moving local reads off to other nodes and this is = causing spikes in read latency ? 

Did you = notice what was happening on the node for the DS to think it was so slow = ? Was compaction or repair going on ? 
 
Have = you played with the badness threshold https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#= L472 ? 

Cheers


http://www.thelastpickle.com

On 24/05/2012, at 5:28 PM, Viktor Jevdokimov = wrote:

 
Best regards = / Pagarbiai
Viktor = Jevdokimov
Senior = Developer

What is = Adform: watch this short = video