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 4693317DA5 for ; Fri, 20 Mar 2015 20:18:06 +0000 (UTC) Received: (qmail 24443 invoked by uid 500); 20 Mar 2015 20:18:03 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 24406 invoked by uid 500); 20 Mar 2015 20:18:03 -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 24396 invoked by uid 99); 20 Mar 2015 20:18:03 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 20 Mar 2015 20:18:03 +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 agarwalpranaya@gmail.com designates 74.125.82.182 as permitted sender) Received: from [74.125.82.182] (HELO mail-we0-f182.google.com) (74.125.82.182) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 20 Mar 2015 20:17:58 +0000 Received: by webcq43 with SMTP id cq43so90576536web.2 for ; Fri, 20 Mar 2015 13:16:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=34/AgRaAQk+51rh/4dc7nWztbOVHKJ9FVqLvjPEbAmM=; b=Mfd2KFJXQ6kiNXVsPo/hxfGtdsVuh4JBCQuOplS/RmSIbMKaww7Wxql6Vdzazundaz tsQ/mfBhx7AMZ8CZhtfxOCuT4REqZ9w7yGkTvJnsXwVGb7QgBHU+x/0NMpT8T9zxY9z4 yFRWHWT/mEBqUFQqRaWCjn5N4DKcHPjH6xejL1/ohDQKdsX0fIiv9e9Rqyj3wOUM0ucM DKsB3C2u+lFH1+hGdLqsbuwunSER7vzS04nr1v7CP3ASOZUhNnq4hGetYnOmIFrpRivS nylR13iQ5i7h2SVwPd7lkF9VD81fBU7wEltIvA1WKHNCX6R4gonvSVsSWe+AEeDkpTGL 8tIA== MIME-Version: 1.0 X-Received: by 10.195.13.168 with SMTP id ez8mr161415374wjd.30.1426882612449; Fri, 20 Mar 2015 13:16:52 -0700 (PDT) Received: by 10.180.73.178 with HTTP; Fri, 20 Mar 2015 13:16:52 -0700 (PDT) In-Reply-To: <550C7F29.2070004@gmail.com> References: <550C7F29.2070004@gmail.com> Date: Fri, 20 Mar 2015 13:16:52 -0700 Message-ID: Subject: Re: Cassandra cluster Too high DISK IOs From: Pranay Agarwal To: user@cassandra.apache.org Content-Type: multipart/alternative; boundary=047d7beba2164058e70511bdffdc X-Virus-Checked: Checked by ClamAV on apache.org --047d7beba2164058e70511bdffdc Content-Type: text/plain; charset=UTF-8 No. as shown in the histograms, 99% of reads are using 2 or less number of tables. What's typical usually? Can anyone share from experience? On Fri, Mar 20, 2015 at 1:12 PM, Duncan Sands wrote: > On 20/03/15 19:34, Pranay Agarwal wrote: > >> The cluster is processing something like 12k reads and 2k writes/seconds. >> The >> disks are locally attached and latency is just fine. It's the number of >> disk >> iops that's too high. >> > > Maybe each read is accessing many sstables. > > Ciao, Duncan. > --047d7beba2164058e70511bdffdc Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
No. as shown in the histograms, 99% of reads are using 2 o= r less number of tables. What's typical usually? Can anyone share from = experience?

= On Fri, Mar 20, 2015 at 1:12 PM, Duncan Sands <duncan.sands@gmail.com= > wrote:
O= n 20/03/15 19:34, Pranay Agarwal wrote:
The cluster is processing something like 12k reads and 2k writes/seconds. T= he
disks are locally attached and latency is just fine. It's the number of= disk
iops that's too high.

 Maybe each read is accessing many sstables.

Ciao, Duncan.

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