From user-return-32512-apmail-cassandra-user-archive=cassandra.apache.org@cassandra.apache.org Fri Mar 8 19:40:48 2013 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 B7B72E86C for ; Fri, 8 Mar 2013 19:40:48 +0000 (UTC) Received: (qmail 94685 invoked by uid 500); 8 Mar 2013 19:40:44 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 94664 invoked by uid 500); 8 Mar 2013 19:40:44 -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 94656 invoked by uid 99); 8 Mar 2013 19:40:44 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 08 Mar 2013 19:40:44 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of edlinuxguru@gmail.com designates 74.125.82.176 as permitted sender) Received: from [74.125.82.176] (HELO mail-we0-f176.google.com) (74.125.82.176) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 08 Mar 2013 19:40:40 +0000 Received: by mail-we0-f176.google.com with SMTP id s43so1423960wey.7 for ; Fri, 08 Mar 2013 11:40:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:content-type; bh=gxOuL/gUH+fR7s9SVt+D3MUZMKHtU7F6DslHrhYvjkU=; b=sCJp1Ka39BJWwoPelGzZNWWyZRtS/ibUjUEkKYVfMuQ6R7vsM9hgtku3P+neXSXTtF +fDkfxDBBfxybCmZrhJ5RCMhaLAH5uqBwujMkT7bxdsEe2X9ogN6HvQIG41OHJ35Ns+y JNdU5HFKX4JWZdsIF4UYoFSi1ulMtf6KKVBq3flHiV/9UmtyYPovSRCiQbZJRn62+zWQ FvpcGBPMReofCiAE8vfUYj6gTzzCp/t+PUm4oGJXBD6eIAlW2I7RUgBvdx4l4zLq5GtU EVyrx9mAa6iDFLWKDqkA2q+W7MWIQ+Cy1Fh5ePHHh+EymebFm+++jt/ZOjp5w0YGeipQ snAQ== MIME-Version: 1.0 X-Received: by 10.194.242.163 with SMTP id wr3mr6356845wjc.35.1362771618716; Fri, 08 Mar 2013 11:40:18 -0800 (PST) Received: by 10.194.61.137 with HTTP; Fri, 8 Mar 2013 11:40:18 -0800 (PST) In-Reply-To: References: Date: Fri, 8 Mar 2013 14:40:18 -0500 Message-ID: Subject: Re: has anyone used dynamic snitch at all From: Edward Capriolo To: user@cassandra.apache.org Content-Type: multipart/alternative; boundary=089e013d1da83e628f04d76efef3 X-Virus-Checked: Checked by ClamAV on apache.org --089e013d1da83e628f04d76efef3 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable dynamic_snitch=3Dtrue is the default. So it is usually on "wrapping" other snitches. I have found several scenarios where it does not work exactly as your would expect. On Fri, Mar 8, 2013 at 2:26 PM, Hiller, Dean wrote: > Our test setup > > 4 nodes, RF=3D3, reads at CL=3DQUOROM and we tried CL=3DTWO > Tell the network card to slow down every packet on node 2 > After fixing astyanax to not go to node 2 anymore, we are still seeing > cassandra have issues as it seems to be involving node 2 somehow. If we > take node 2 down, it all speeds back up. > > We are trying to get this working such that a slow node in cassandra does > not impact our customers. > > We are in 1.2.2 and added the following properties=85.(our properties sho= w > PropertyFileSnitch though I see the keyspace has > org.apache.cassandra.locator.SimpleStrategy set probably because it was > created through a tool instead of CLI=85shucks)=85.anyways, I still expec= ted > dynamic snitch to work=85. > > # controls how often to perform the more expensive part of host score > # calculation > dynamic_snitch: true > dynamic_snitch_update_interval_in_ms: 100 > # controls how often to reset all host scores, allowing a bad host to > # possibly recover > dynamic_snitch_reset_interval_in_ms: 600000 > # if set greater than zero and read_repair_chance is < 1.0, this will all= ow > # 'pinning' of replicas to hosts in order to increase cache capacity. > # The badness threshold will control how much worse the pinned host has t= o > be > # before the dynamic snitch will prefer other replicas over it. This is > # expressed as a double which represents a percentage. Thus, a value of > # 0.2 means Cassandra would continue to prefer the static snitch values > # until the pinned host was 20% worse than the fastest. > dynamic_snitch_badness_threshold: 0.1 > > Any help appreciated, > Thanks, > Dean > --089e013d1da83e628f04d76efef3 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable dynamic_snitch=3Dtrue is the default. So it is usually on "wrapping&qu= ot; other snitches. I have found several scenarios where it does not work e= xactly as your would expect.

On Fri, Mar = 8, 2013 at 2:26 PM, Hiller, Dean <Dean.Hiller@nrel.gov> w= rote:
Our test setup

4 nodes, RF=3D3, reads at CL=3DQUOROM and we tried CL=3DTWO
Tell the network card to slow down every packet on node 2
After fixing astyanax to not go to node 2 anymore, we are still seeing cass= andra have issues as it seems to be involving node 2 somehow. =A0If we take= node 2 down, it all speeds back up.

We are trying to get this working such that a slow node in cassandra does n= ot impact our customers.

We are in 1.2.2 and added the following properties=85.(our properties show = PropertyFileSnitch though I see the keyspace has org.apache.cassandra.locat= or.SimpleStrategy set probably because it was created through a tool instea= d of CLI=85shucks)=85.anyways, I still expected dynamic snitch to work=85.<= br>
# controls how often to perform the more expensive part of host score
# calculation
dynamic_snitch: true
dynamic_snitch_update_interval_in_ms: 100
# controls how often to reset all host scores, allowing a bad host to
# possibly recover
dynamic_snitch_reset_interval_in_ms: 600000
# if set greater than zero and read_repair_chance is < 1.0, this will al= low
# 'pinning' of replicas to hosts in order to increase cache capacit= y.
# The badness threshold will control how much worse the pinned host has to = be
# before the dynamic snitch will prefer other replicas over it. =A0This is<= br> # expressed as a double which represents a percentage. =A0Thus, a value of<= br> # 0.2 means Cassandra would continue to prefer the static snitch values
# until the pinned host was 20% worse than the fastest.
dynamic_snitch_badness_threshold: 0.1

Any help appreciated,
Thanks,
Dean

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