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 A631D7638 for ; Mon, 21 Nov 2011 08:31:23 +0000 (UTC) Received: (qmail 30424 invoked by uid 500); 21 Nov 2011 08:31:21 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 30390 invoked by uid 500); 21 Nov 2011 08:31:21 -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 30382 invoked by uid 99); 21 Nov 2011 08:31:21 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 21 Nov 2011 08:31:21 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=FREEMAIL_FROM,HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of watcherfr@gmail.com designates 74.125.82.42 as permitted sender) Received: from [74.125.82.42] (HELO mail-ww0-f42.google.com) (74.125.82.42) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 21 Nov 2011 08:31:14 +0000 Received: by wwe3 with SMTP id 3so5131035wwe.1 for ; Mon, 21 Nov 2011 00:30:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=lG0dMi4lV78NdzlGZxLUhZ/kszPnMpFh5oY5AV3X0Kg=; b=SgjBxUJ2aBnwptDgmz2Kp6KUhWML52Wr8WwZuBHZzBFgU6lGVwGLED3wdeZUQanZ0B ol2xum4whURqGMj8/022yI5Oq5z80ntvg6rfjOqOP62j0tSkmVcz7KZZ+3ykdnWtvMJ7 eNFlsqYLV3nV+Ucq96C+ttjKnIMju7ltfzH80= MIME-Version: 1.0 Received: by 10.180.92.169 with SMTP id cn9mr12404157wib.62.1321864253673; Mon, 21 Nov 2011 00:30:53 -0800 (PST) Received: by 10.180.83.70 with HTTP; Mon, 21 Nov 2011 00:30:53 -0800 (PST) Received: by 10.180.83.70 with HTTP; Mon, 21 Nov 2011 00:30:53 -0800 (PST) In-Reply-To: References: <4EC54BE9.1000605@bnl.gov> Date: Mon, 21 Nov 2011 09:30:53 +0100 Message-ID: Subject: Re: What sort of load do the tombstones create on the cluster? From: Philippe To: user@cassandra.apache.org Cc: potekhin@bnl.gov Content-Type: multipart/alternative; boundary=f46d0435c068480fb804b23a8137 X-Virus-Checked: Checked by ClamAV on apache.org --f46d0435c068480fb804b23a8137 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable I don't remember your exact situation but could it be your network connectivity? I know I've been upgrading mine because I'm maxing out fastethernet on a 12 node cluster. Le 20 nov. 2011 22:54, "Jahangir Mohammed" a =E9crit : > Mostly, they are I/O and CPU intensive during major compaction. If gangli= a > doesn't have anything suspicious there, then what is performance loss ? > Read or write? > On Nov 17, 2011 1:01 PM, "Maxim Potekhin" wrote: > >> In view of my unpleasant discovery last week that deletions in Cassandra >> lead to a very real >> and serious performance loss, I'm working on a strategy of moving forwar= d. >> >> If the tombstones do cause such problem, where should I be looking for >> performance bottlenecks? >> Is it disk, CPU or something else? Thing is, I don't see anything >> outstanding in my Ganglia plots. >> >> TIA, >> >> Maxim >> >> --f46d0435c068480fb804b23a8137 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable

I don't remember your exact situation but could it be your network c= onnectivity?
I know I've been upgrading mine because I'm maxing out fastethernet= on a 12 node cluster.

Le 20 nov. 2011 22:54, "Jahangir Mohammed&q= uot; <md.jahangir27@gmail.com= > a =E9crit=A0:

Mostly, they are I/O and CPU intensive during major compaction. If gangl= ia doesn't have anything suspicious there, then what is performance los= s ? Read or write?

On Nov 17, 2011 1:01 PM, "Maxim Potekhin&qu= ot; <potekhin@bnl.= gov> wrote:
In view of my unpleasant discovery last week that deletions in Cassandra le= ad to a very real
and serious performance loss, I'm working on a strategy of moving forwa= rd.

If the tombstones do cause such problem, where should I be looking for perf= ormance bottlenecks?
Is it disk, CPU or something else? Thing is, I don't see anything outst= anding in my Ganglia plots.

TIA,

Maxim

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