From owner-freebsd-fs@FreeBSD.ORG Mon Jun 13 09:29:08 2011 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 6C0F4106566B for ; Mon, 13 Jun 2011 09:29:08 +0000 (UTC) (envelope-from numisemis@gmail.com) Received: from mail-bw0-f54.google.com (mail-bw0-f54.google.com [209.85.214.54]) by mx1.freebsd.org (Postfix) with ESMTP id E46618FC19 for ; Mon, 13 Jun 2011 09:29:07 +0000 (UTC) Received: by bwz12 with SMTP id 12so5244636bwz.13 for ; Mon, 13 Jun 2011 02:29:06 -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; bh=TDY5QwLagz84ziNl1vImo/YLQP8RhKxvIo5EuWwGPUY=; b=kP/zPFgQNwye+b72v1va2aKTgH9ypqXAm9xhqD3poi0UjilRZJtS5t4PR6NEVrrXhd dbb+ZYb4oQ8D7E56amaVven8CVWwz9HcE7thaYPZkhdq+BCqSK3gIv7xt8rDXFOmnmf0 yWhPNvlU3OWCTgCsvAzbFHMXKRQ09VJx+AhaE= 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; b=PhVVY6oYEcUfzazbJfj6AOngmkxd+sGdnus7u9dxNVbSNT9Ros+IE5cxUejY/YTaeI AD6yETTTiMJTbfzWLwealUzWbEVJI5mF1xVxhIG2Ms6ZodRmMPi15ksNSCYX/aJvYtU4 O7nXfHK6zl637SV1l123HtIrX/dw5qwMm0jvQ= MIME-Version: 1.0 Received: by 10.205.81.193 with SMTP id zz1mr4389621bkb.3.1307957346509; Mon, 13 Jun 2011 02:29:06 -0700 (PDT) Received: by 10.204.180.139 with HTTP; Mon, 13 Jun 2011 02:29:06 -0700 (PDT) In-Reply-To: References: Date: Mon, 13 Jun 2011 11:29:06 +0200 Message-ID: From: =?UTF-8?Q?=C5=A0imun_Mikecin?= To: Steven Hartland , freebsd-fs@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: Subject: Re: Impossible compression ratio on ZFS X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Jun 2011 09:29:08 -0000 2011/6/13 Steven Hartland > I've just done an optimisation of a mysql table which is located > on a compressed zfs partition and spotted that the size reported > by du is impossibly small for the file:- > > du -h detail* > 1.5K detail.frm > 7.5K detail.ibd > > ls -l detail* > -rw-rw---- 1 mysql mysql 8660 Jun 13 10:00 detail.frm > -rw-rw---- 1 mysql mysql 650117120 Jun 13 10:04 detail.ibd > > The table format for those interested is 3 int's, 3 indexes and > contains 8million rows. > > I highly doubt that my 620MB table is taking up just 7.5K on disk > any ideas? > It is possible if the file detail.ibd is mostly filled with zeros (that would be the case unless you have 620MB of real data).