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 9F55B17555 for ; Mon, 2 Feb 2015 04:35:14 +0000 (UTC) Received: (qmail 49873 invoked by uid 500); 2 Feb 2015 04:34:57 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 49831 invoked by uid 500); 2 Feb 2015 04:34:57 -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 49816 invoked by uid 99); 2 Feb 2015 04:34:57 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 02 Feb 2015 04:34:57 +0000 X-ASF-Spam-Status: No, hits=3.7 required=5.0 tests=FORGED_YAHOO_RCVD,FREEMAIL_ENVFROM_END_DIGIT,FREEMAIL_REPLYTO_END_DIGIT,HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of cnet62@yahoo.com designates 98.138.121.64 as permitted sender) Received: from [98.138.121.64] (HELO nm45-vm0.bullet.mail.ne1.yahoo.com) (98.138.121.64) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 02 Feb 2015 04:34:30 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1422851668; bh=cM3ZN2oRo/yTlGEomTDmu94xz1zbUTBIjJvYL/Lbj6E=; h=Date:From:Reply-To:To:In-Reply-To:References:Subject:From:Subject; b=V/osYI7XZNxbqUQegznsBGIbqdy9DRLFGpa8vqjaOOLbdmDE4cHsQJtHooPuN4mqfaunV0zJKlEh/P4Qx0FK5LVgqq1xVIzel+Sxfu9wIb0vcj4nWAW/bkmGDOhpbyhVUNiklXRrratbCyYnINDTjL1saqjfJKQzHIVQ9F+HsHjFrg/UcHLuGROqqGzT+PsG6pHLDSarw0CHarus0Ygazqz+6TqBC5dyIECkXHlwjMPxKNzMtpN+BTuN5bxUFqP4OQrlDBvkq50y7Km/N2028G77wU5QMo8OPnpmqeNKXUqKSxfy4SFW/6Nt+KAVOEiXgF0NSpLFugAx6hseAdKQXA== Received: from [127.0.0.1] by nm45.bullet.mail.ne1.yahoo.com with NNFMP; 02 Feb 2015 04:34:28 -0000 Received: from [98.138.101.128] by nm45.bullet.mail.ne1.yahoo.com with NNFMP; 02 Feb 2015 04:31:47 -0000 Received: from [98.138.89.254] by tm16.bullet.mail.ne1.yahoo.com with NNFMP; 02 Feb 2015 04:31:47 -0000 Received: from [127.0.0.1] by omp1046.mail.ne1.yahoo.com with NNFMP; 02 Feb 2015 04:31:47 -0000 X-Yahoo-Newman-Property: ymail-4 X-Yahoo-Newman-Id: 55244.98444.bm@omp1046.mail.ne1.yahoo.com X-YMail-OSG: F0AuJJgVM1mA6ryJlzfybVZ7uHmwAtFq1ow5agaNHKnS6EGKCU.m2Vb4ZvRKWZH 19tOHDvN4Gh4.eEgWSI.cjnbAnCIPJoIphiZ1Lv5tNViA9q99C7GMTMtViikhqSY9l.upI.Az2J9 SePuyg4nyJL4fQ8.Ldf.oIYq9dgSrCgujFZ9DNkm_1zqmYFDia1TPpqlzBbpWKJs2t4_E9oayGew y9LQEhhTBUh9kW7orekdu6GDbLMYRuRCrJv21KweFlGzKvJh2lv396fedDICNUdkCZp0wZ9B9Wbe 6wnn6hsWMsIshgBQilA5CMI.C.flkbg43Nnpzt1QNb_Sp5iFhresszKGURn2.DgLkDmPvVtpH.HO NHzF_bm_02xqYmIk33IZKiXsGgBb_0WxoDHVufXFIFANxneQx1HWzzfB3tmnrs9CCRa8nPzXOBzy bFHQHXhuJV.83bCW2Z4xTDHkMQnc3Uz3tHmcPekiLcSD5RUTu.zJf0XmGYVL.xL8sReacN_VT.eY 8xcj3FpFMFAVrvmX8LvqymaDzXt83LYL._dLBMXKPWhTHRNDj_N5EINbBVtr3iibV709fAU0o50S EwMGH.DtUQxIxR0i7FnM3Tt8.rAA- Received: by 98.138.105.245; Mon, 02 Feb 2015 04:31:46 +0000 Date: Mon, 2 Feb 2015 04:31:46 +0000 (UTC) From: Jan Reply-To: Jan To: "user@cassandra.apache.org" Message-ID: <2134516680.422388.1422851506125.JavaMail.yahoo@mail.yahoo.com> In-Reply-To: References: Subject: Re: Any problem mounting a keyspace directory in ram memory? MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_422387_1257530783.1422851506114" X-Virus-Checked: Checked by ClamAV on apache.org ------=_Part_422387_1257530783.1422851506114 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable HI Gabriel;=C2=A0 I don't think Apache Cassandra supports in-memory keyspaces.=C2=A0However D= atastax Enterprise does support it.=C2=A0 Quoting from Datastax:=C2=A0DataStax Enterprise includes the in-memory opti= on for storing data to and accessing data from memory exclusively. No disk = I/O occurs. Consider using the in-memory option for storing a modest amount= of data, mostly composed of overwrites, such as an application for mirrori= ng stock exchange data. Only the prices fluctuate greatly while the keys fo= r the data remain relatively constant. Generally, the table you design for = use in-memory should have the following characteristics: =20 - Store a small amount of data - Experience a workload that is mostly overwrites - Be heavily trafficked Using the in-memory option | DataStax Enterprise 4.0 Documentation | =C2=A0 | | =C2=A0 | =C2=A0 | =C2=A0 | =C2=A0 | =C2=A0 | | Using the in-memory option | DataStax Enterprise 4.0 DocumentationUsing t= he in-memory option | | | | View on www.datastax.com | Preview by Yahoo | | | | =C2=A0 | =C2=A0 hope this helpsJan C* Architect =20 On Sunday, February 1, 2015 1:32 PM, Gabriel Menegatti wrote: =20 Hi guys, Please,=C2=A0does anyone here already mounted a specific=C2=A0keyspace dire= ctory to ram memory using tmpfs? Do you see any problem doing so, except by the fact that the data can be lo= st? Thanks in advance. Regards,Gabriel. ------=_Part_422387_1257530783.1422851506114 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
HI Gabriel; 

I don't think = Apache Cassandra supports in-memory keyspaces. 
However Datastax Enterprise does support it. =

Quoting from Datastax: 
Data= Stax Enterprise includes the in-memory option for storing data to and acces= sing data from memory exclusively. No disk I/O occurs. Consider using the i= n-memory option for storing a modest amount of data, mostly composed of ove= rwrites, such as an application for mirroring stock exchange data. Only the= prices fluctuate greatly while the keys for the data remain relatively con= stant. Generally, the table you design for use in-memory should have the fo= llowing characteristics:
  • Store a small amo= unt of data
  • Experience a workload that is mostly overwrites
    • <= li class=3D"" style=3D"margin-top: 5px; margin-bottom: 16px;" id=3D"yui_3_1= 6_0_1_1422850905449_9558">Be heavily trafficked
 

hope this helps
Jan=

C* Architect



=
On Sunday, February 1, 2= 015 1:32 PM, Gabriel Menegatti <gabriel@s1mbi0se.com.br> wrote:
<= /font>


Hi guys,

Please, does anyone= here already mounted a specific keyspace directory to ram memory usin= g tmpfs?

Do you see any problem doing so, except b= y the fact that the data can be lost?

Thanks in ad= vance.

Regards,
Gabriel.


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