From cassandra-user-return-1653-apmail-incubator-cassandra-user-archive=incubator.apache.org@incubator.apache.org Fri Dec 04 20:23:08 2009 Return-Path: Delivered-To: apmail-incubator-cassandra-user-archive@minotaur.apache.org Received: (qmail 32670 invoked from network); 4 Dec 2009 20:23:08 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.3) by minotaur.apache.org with SMTP; 4 Dec 2009 20:23:08 -0000 Received: (qmail 79922 invoked by uid 500); 4 Dec 2009 20:23:08 -0000 Delivered-To: apmail-incubator-cassandra-user-archive@incubator.apache.org Received: (qmail 79913 invoked by uid 500); 4 Dec 2009 20:23:08 -0000 Mailing-List: contact cassandra-user-help@incubator.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: cassandra-user@incubator.apache.org Delivered-To: mailing list cassandra-user@incubator.apache.org Received: (qmail 79904 invoked by uid 99); 4 Dec 2009 20:23:08 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 04 Dec 2009 20:23:08 +0000 X-ASF-Spam-Status: No, hits=2.2 required=10.0 tests=HTML_MESSAGE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of driftx@gmail.com designates 209.85.221.191 as permitted sender) Received: from [209.85.221.191] (HELO mail-qy0-f191.google.com) (209.85.221.191) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 04 Dec 2009 20:23:00 +0000 Received: by qyk29 with SMTP id 29so1139060qyk.32 for ; Fri, 04 Dec 2009 12:22:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=s/Wnp5xkVgtT5Tc5YHQuen4zE6IVqzwjVlYFnmUoon0=; b=kxAvoPqtiSvUP4zuWFAn1J6kFv7jILZi2Tt0Mvww3v3WyKwHbvGcWFzCinak773iwm s4gs1DeNS9V36xdIZfhxHa1GmpuJdD9KZQzk3m0+1Z1BGMZ4tqRWJfmwmJaMJcCCeXyf eiS0dbvjRp0e2Eh9woGik+0hbVnrzjxjrtfXE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=FplfTLLFA7u7S4vng/V5satKewHICBPy/zt3FZFknO4ybiu0zIJ9CXHEazHgQrs7Vy /UGTPlUnVlmI5LQLcPoWj4GLCWI+rv7Dhp8gN3+ppHwsAyM3m9S4N00hAYkYj27k1WXg C/DU0s+A+kJZhVPeMxsixesI8/P1PXYQDLgQU= MIME-Version: 1.0 Received: by 10.229.100.221 with SMTP id z29mr516283qcn.18.1259958159291; Fri, 04 Dec 2009 12:22:39 -0800 (PST) In-Reply-To: <1259955614.2898.97.camel@btoddb-laptop> References: <59DD1BA8FD3C0F4C90771C18F2B5B53A4C850190C6@GVW0432EXB.americas.hpqcorp.net> <59DD1BA8FD3C0F4C90771C18F2B5B53A4C850C22D8@GVW0432EXB.americas.hpqcorp.net> <59DD1BA8FD3C0F4C90771C18F2B5B53A4C850C2317@GVW0432EXB.americas.hpqcorp.net> <59DD1BA8FD3C0F4C90771C18F2B5B53A4C85126629@GVW0432EXB.americas.hpqcorp.net> <1259953660.2898.96.camel@btoddb-laptop> <1259955614.2898.97.camel@btoddb-laptop> Date: Fri, 4 Dec 2009 14:22:38 -0600 Message-ID: Subject: Re: Persistently increasing read latency From: Brandon Williams To: cassandra-user@incubator.apache.org Content-Type: multipart/alternative; boundary=00163649968f8434af0479ecde2d X-Virus-Checked: Checked by ClamAV on apache.org --00163649968f8434af0479ecde2d Content-Type: text/plain; charset=ISO-8859-1 On Fri, Dec 4, 2009 at 1:40 PM, B. Todd Burruss wrote: > i've actually allocatted plenty of RAM, but it isn't fully used. the > read performance dwindles well before reaching a RAM limit. You don't want to over-allocate memory to Cassandra, you want to leave as much free as you can so the OS can cache the reads for you. -Brandon --00163649968f8434af0479ecde2d Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
On Fri, Dec 4, 2009 at 1:40 PM, B. Todd Burruss = <bburruss@real.co= m> wrote:
i've actually allocatted plenty of RAM, but it isn't fully used. = =A0the
read performance dwindles well before reaching a RAM limit.

You don't want to over-allocate memory to Cassandra, y= ou want to leave as much free as you can so the OS can cache the reads for = you.

-Brandon

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