Return-Path: Delivered-To: apmail-cassandra-dev-archive@www.apache.org Received: (qmail 42716 invoked from network); 9 Jul 2010 06:54:07 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 9 Jul 2010 06:54:07 -0000 Received: (qmail 57208 invoked by uid 500); 9 Jul 2010 06:54:06 -0000 Delivered-To: apmail-cassandra-dev-archive@cassandra.apache.org Received: (qmail 56780 invoked by uid 500); 9 Jul 2010 06:54:03 -0000 Mailing-List: contact dev-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@cassandra.apache.org Delivered-To: mailing list dev@cassandra.apache.org Received: (qmail 56763 invoked by uid 99); 9 Jul 2010 06:54:02 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 09 Jul 2010 06:54:02 +0000 X-ASF-Spam-Status: No, hits=0.7 required=10.0 tests=RCVD_IN_DNSWL_NONE,SPF_NEUTRAL X-Spam-Check-By: apache.org Received-SPF: neutral (nike.apache.org: local policy) Received: from [74.125.82.172] (HELO mail-wy0-f172.google.com) (74.125.82.172) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 09 Jul 2010 06:53:53 +0000 Received: by wyb40 with SMTP id 40so1288388wyb.31 for ; Thu, 08 Jul 2010 23:52:33 -0700 (PDT) MIME-Version: 1.0 Received: by 10.227.155.82 with SMTP id r18mr1903557wbw.70.1278658352793; Thu, 08 Jul 2010 23:52:32 -0700 (PDT) Sender: scode@scode.org Received: by 10.216.61.12 with HTTP; Thu, 8 Jul 2010 23:52:32 -0700 (PDT) X-Originating-IP: [90.233.12.91] In-Reply-To: References: Date: Fri, 9 Jul 2010 08:52:32 +0200 X-Google-Sender-Auth: XpqUA-KJ8aqpxU9jCaqtkOBjGQY Message-ID: Subject: Re: Minimizing the impact of compaction on latency and throughput From: Peter Schuller To: dev@cassandra.apache.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Virus-Checked: Checked by ClamAV on apache.org > It might be worth experimenting with posix_fadvise. =C2=A0I don't think > implementing our own i/o scheduler or rate-limiter would be as good a > use of time (it sounds like you're on that page too). Ok. And yes I mostly agree, although I can imagine circumstances where a pretty simple rate limiter might help significantly - albeit be something that has to be tweaked very specifically for the situation/hardware rather than being auto-tuned. If I have the time I may look into posix_fadvise() to begin with (but I'm not promising anything). Thanks for the input! --=20 / Peter Schuller