From user-return-17278-apmail-cassandra-user-archive=cassandra.apache.org@cassandra.apache.org Thu Jun 2 14:10:30 2011 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 E02764DDB for ; Thu, 2 Jun 2011 14:10:29 +0000 (UTC) Received: (qmail 94495 invoked by uid 500); 2 Jun 2011 14:10:27 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 94474 invoked by uid 500); 2 Jun 2011 14:10:27 -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 94466 invoked by uid 99); 2 Jun 2011 14:10:27 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 02 Jun 2011 14:10:27 +0000 X-ASF-Spam-Status: No, hits=-0.7 required=5.0 tests=FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,RFC_ABUSE_POST,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of edlinuxguru@gmail.com designates 209.85.210.172 as permitted sender) Received: from [209.85.210.172] (HELO mail-iy0-f172.google.com) (209.85.210.172) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 02 Jun 2011 14:10:22 +0000 Received: by iyn15 with SMTP id 15so964257iyn.31 for ; Thu, 02 Jun 2011 07:10:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:date :message-id:subject:from:to:content-type:content-transfer-encoding; bh=95c3Hw35greimEaPrK7+sSQobb2cggDr1YNJnAEGqlo=; b=wkW7ZuufAFD3H4fABetFpmySVa77LL1JA8h59vjaaQmZqir1oxsxjIzG+qDGrQ6XhT qvBZ84YuH7lyhIZh8yN3a2Zeu7SrDfeDoQw5AqMwR5kkwK+sUUczo7Um+Rh1qOhLM+Au tlU6ot67It/J1716vFwAgOQmlYQx7X336T1No= 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:content-transfer-encoding; b=VQW4GLXXlLpRE8c8IDg7NB8vf+pGhiChsn8onFmKNgz3NNOK1O/E/DF2rX2ZSq3/bn w+PNwJ3S4koRflwcUPhdAEsOPWQ5mnOQjqsmWGqSPAzbhWzTF0YgFJ12uZgAcbSVWeq6 ZpvI11bI2eXgWcLQJtsm6i15luZTiygNIjb+Y= MIME-Version: 1.0 Received: by 10.42.133.8 with SMTP id f8mr1727984ict.176.1307023801849; Thu, 02 Jun 2011 07:10:01 -0700 (PDT) Received: by 10.42.164.138 with HTTP; Thu, 2 Jun 2011 07:10:01 -0700 (PDT) In-Reply-To: References: Date: Thu, 2 Jun 2011 10:10:01 -0400 Message-ID: Subject: Re: sync commitlog in batch mode lose data From: Edward Capriolo To: "user@cassandra.apache.org" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Your Losing data because at level quorm with 2 nodes becomes all. Cassandra will not even try to write data after the node goes down . Client should see unavailableexception. For a small window after the failure you will see timedoutexception and those writes should hit the commitlog. On Wednesday, June 1, 2011, leon hong wrote: > wait "geili"=A0reply > > 2011/6/1 Preston Chang > > I disable the disk cache of RAID controller, =A0unfortunately it still lo= st some data. > > 2011/6/1 Peter Schuller > > > >> 1). set commitlog sync in batch mode and the sync batch window in 0 ms >> 2). one client wrote random keys in infinite loop with consistency level >> QUORUM and record the keys in file after the insert()=A0method return no= rmally >> 3). unplug one server (node A) power cord >> 4). restart the server and cassandra service >> 5). read the key list generated in step 2) with consistency level ONE > > How sure are you that the system is honoring fsync() properly, > including flushing any caches on underlying drives? Or is this with > battery backed caching RAID controllers? > > -- > / Peter Schuller > > > -- > by Preston Chang > > > >