From owner-freebsd-fs@FreeBSD.ORG Wed Mar 5 09:28:50 2014 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id B15B86CA for ; Wed, 5 Mar 2014 09:28:50 +0000 (UTC) Received: from mail-yh0-x235.google.com (mail-yh0-x235.google.com [IPv6:2607:f8b0:4002:c01::235]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 6A3FDFC8 for ; Wed, 5 Mar 2014 09:28:50 +0000 (UTC) Received: by mail-yh0-f53.google.com with SMTP id v1so705411yhn.12 for ; Wed, 05 Mar 2014 01:28:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=BFD8dXNziphn8RNtKPbgs7b1VCr/94A6QmDNJc+TrmA=; b=L+SX9R7IhzNfMi45p2zohrLRmeUuEDlTDn8tpsyfub/4DCQZ9Z7YIBu4buH0zunu+H 7Xesbbyyk+qfMqwx/qfcogF2Vsz4FP/lDYpVL/dxzyksUQe6UEGijVb+6ZENfWMHYV2g 0sslW2WxBFwu1ZCbimZkt1POAr1ZGnyZpKG8gAcreS8o+iRlgc6kwZkxKAFCTnx41bZn K7QZYQvwNhu4Ybp0a9f4WkSkWDDwomps+V7ShK9V4bfqxtWxSpPn2hLageL+TUyqDnHo JgMxfEvS5KqsLoiTnJEqHDGJ1MeTw0k+TYT+Jd3lkQWP5yY864Z6a6Do+Guu+DDZYBon vQUA== MIME-Version: 1.0 X-Received: by 10.236.159.65 with SMTP id r41mr5658397yhk.20.1394011729542; Wed, 05 Mar 2014 01:28:49 -0800 (PST) Received: by 10.170.54.17 with HTTP; Wed, 5 Mar 2014 01:28:49 -0800 (PST) In-Reply-To: References: <53157CC2.8080107@FreeBSD.org> <5315D446.3040701@freebsd.org> Date: Wed, 5 Mar 2014 09:28:49 +0000 Message-ID: Subject: Re: Is LZ4 compression of the ZFS L2ARC available in any RELEASE/STABLE? From: krad To: Olav Gjerde Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.17 Cc: FreeBSD FS X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Mar 2014 09:28:50 -0000 I thought the recordsize referred to the maximum block size rather than the actual block size. Please correct me if im wrong On 5 March 2014 07:17, Olav Gjerde wrote: > Currently I've set the recordsize to 8k, however I'm thinking maybe a > recordsize of 4k may more optimal? > This is because the compressratio with LZ4 is around 2.5 and this value h= as > been constant for all my data while growing from a few megabytes to a > tenfold of gigabytes. > Maybe something I should play with to see if it makes a difference. > > > On Wed, Mar 5, 2014 at 3:40 AM, Bob Friesenhahn < > bfriesen@simple.dallas.tx.us> wrote: > > > On Tue, 4 Mar 2014, Olav Gjerde wrote: > > > > I managed to mess up who I replied to and Matthew replied back with a > good > >> answer which I think didn't reach the mailing list. > >> > >> I actually have a problem with query performance in one of my database= s > >> related to running PostgreSQL on ZFS. Which is why I'm so interested i= n > >> compression for the L2ARC Cache. The problem is random IO read were > >> creating a report were I aggregate 75000 rows takes 30 minutes!!! The > >> table > >> that I query has 400 million rows though. > >> The dataset easily fit in memory, so if I run the same query again it > >> takes > >> less than a second. > >> > > > > Make sure that your database is on a filesystem with zfs block-size > > matching the database block-size (rather than 128K). Otherwise far mor= e > > data may be read than needed, and likewise, writes may result in writin= g > > far more data than needed. > > > > Regardless, L2ARC on SSD is a very good idea for this case. > > > > Bob > > -- > > Bob Friesenhahn > > bfriesen@simple.dallas.tx.us, > http://www.simplesystems.org/users/bfriesen/ > > GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ > > > > > > -- > Olav Gr=F8n=E5s Gjerde > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" >