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 8F31D9889 for ; Mon, 13 Feb 2012 08:05:47 +0000 (UTC) Received: (qmail 2039 invoked by uid 500); 13 Feb 2012 08:05:43 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 1611 invoked by uid 500); 13 Feb 2012 08:05:16 -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 1603 invoked by uid 99); 13 Feb 2012 08:05:10 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 13 Feb 2012 08:05:10 +0000 X-ASF-Spam-Status: No, hits=2.2 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_NEUTRAL X-Spam-Check-By: apache.org Received-SPF: neutral (nike.apache.org: local policy) Received: from [209.85.212.44] (HELO mail-vw0-f44.google.com) (209.85.212.44) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 13 Feb 2012 08:05:02 +0000 Received: by vbbfr13 with SMTP id fr13so3442111vbb.31 for ; Mon, 13 Feb 2012 00:04:41 -0800 (PST) MIME-Version: 1.0 Received: by 10.52.35.69 with SMTP id f5mr6646507vdj.29.1329120280935; Mon, 13 Feb 2012 00:04:40 -0800 (PST) Received: by 10.52.35.75 with HTTP; Mon, 13 Feb 2012 00:04:40 -0800 (PST) In-Reply-To: References: <201202131403484201571@jike.com> Date: Mon, 13 Feb 2012 09:04:40 +0100 Message-ID: Subject: Re: keycache persisted to disk ? From: "R. Verlangen" To: user@cassandra.apache.org Content-Type: multipart/alternative; boundary=20cf307cfcd4357c1f04b8d3eed2 X-Gm-Message-State: ALoCoQk7cwfORfb2Qn1sG1hdVgtMUdVj0qiJ9fLhPM2+CfpzizJjhnJpCWIZdyGynK5nY8UosG25 X-Virus-Checked: Checked by ClamAV on apache.org --20cf307cfcd4357c1f04b8d3eed2 Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: quoted-printable This is because of the "warm up" of Cassandra as it starts. On a start it will start fetching the rows that were cached: this will have to be loaded from the disk, as there is nothing in the cache yet. You can read more about this at http://wiki.apache.org/cassandra/LargeDataSetConsiderations 2012/2/13 Franc Carter > On Mon, Feb 13, 2012 at 5:03 PM, zhangcheng wrote: > >> ** >> >> I think the keycaches and rowcahches are bothe persisted to disk when >> shutdown, and restored from disk when restart, then improve the performa= nce. >> > > Thanks - that would explain at least some of what I am seeing > > cheers > > >> >> 2012-02-13 >> ------------------------------ >> zhangcheng >> ------------------------------ >> *=B7=A2=BC=FE=C8=CB=A3=BA* Franc Carter >> *=B7=A2=CB=CD=CA=B1=BC=E4=A3=BA* 2012-02-13 13:53:56 >> *=CA=D5=BC=FE=C8=CB=A3=BA* user >> *=B3=AD=CB=CD=A3=BA* >> *=D6=F7=CC=E2=A3=BA* keycache persisted to disk ? >> >> Hi, >> >> I am testing Cassandra on Amazon and finding performance can vary fairly >> wildly. I'm leaning towards it being an artifact of the AWS I/O system b= ut >> have one other possibility. >> >> Are keycaches persisted to disk and restored on a clean shutdown and >> restart ? >> >> cheers >> >> -- >> >> *Franc Carter* | Systems architect | Sirca Ltd >> >> >> franc.carter@sirca.org.au | www.sirca.org.au >> >> Tel: +61 2 9236 9118 >> >> Level 9, 80 Clarence St, Sydney NSW 2000 >> >> PO Box H58, Australia Square, Sydney NSW 1215 >> >> > > > -- > > *Franc Carter* | Systems architect | Sirca Ltd > > > franc.carter@sirca.org.au | www.sirca.org.au > > Tel: +61 2 9236 9118 > > Level 9, 80 Clarence St, Sydney NSW 2000 > > PO Box H58, Australia Square, Sydney NSW 1215 > > --20cf307cfcd4357c1f04b8d3eed2 Content-Type: text/html; charset=GB2312 Content-Transfer-Encoding: quoted-printable This is because of the "warm up" of Cassandra as it starts. On a = start it will start fetching the rows that were cached: this will have to b= e loaded from the disk, as there is nothing in the cache yet. You can read = more about this at  htt= p://wiki.apache.org/cassandra/LargeDataSetConsiderations 

<= div class=3D"gmail_quote">2012/2/13 Franc Carter <franc.carter@sirca.org.au><= /span>
On Mon, Feb 13, 2012 at 5:= 03 PM, zhangcheng <zhangcheng@jike.com> wrote:
 
I think the keycaches and=20 rowcahches are bothe persisted to disk when shutdown, and restored from dis= k=20 when restart, then improve the performance.
=

Thanks - that would explain at least some of what I am seein= g

cheers
 
 
2012-02-13
zhangcheng=20
=B7=A2=BC=FE=C8=CB=A3=BA Franc Carter
=B7=A2=CB=CD=CA=B1=BC=E4=A3=BA 201= 2-02-13  13:53:56=20
=CA=D5=BC=FE=C8=CB=A3=BA user
=B3=AD=CB=CD=A3=BA
=D6=F7=CC=E2=A3=BA keycache persisted to= disk ?=20

Hi,

I am testing Cassandra on Amazon= =20 and finding performance can vary fairly wildly. I'm leaning towards it = being an=20 artifact of the AWS I/O system but have one other possibility.

Are= =20 keycaches persisted to disk and restored on a clean shutdown and restart ?<= br clear=3D"all">
cheers

--

Franc Carter<= /b>=20 | Systems architect=20 | Sir= ca=20 Ltd

franc.carter@sirca.or= g.au |=  www.sirca.org.au

Tel:=  +61 2 9236 9118

Level 9, 80=20 Clarence St, Sydney NSW 2000=

PO=20 Box H58, Australia Square, Sydney NSW=20 1215



=

--

Franc Carter<= /b> |<= /span> Systems architect | Sirca Ltd

franc.carter@sirca.org.au | www.sirca.org.au

Tel:=  +61 2 9236 9118

Level 9, 80 Clarence St, Sydney NSW 2000

PO Box H58, Australia Square, Sydney NSW 1215<= /span>



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