From owner-freebsd-questions@FreeBSD.ORG Sun Aug 9 09:13:12 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 92C8D106566B for ; Sun, 9 Aug 2009 09:13:12 +0000 (UTC) (envelope-from kraduk@googlemail.com) Received: from mail-bw0-f206.google.com (mail-bw0-f206.google.com [209.85.218.206]) by mx1.freebsd.org (Postfix) with ESMTP id 0FB878FC1F for ; Sun, 9 Aug 2009 09:13:11 +0000 (UTC) Received: by bwz2 with SMTP id 2so1535717bwz.43 for ; Sun, 09 Aug 2009 02:13:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type; bh=DfBpFxpsnFzkXhsxH/8PajsJhDIdZQ4sCtukNIFEDVI=; b=AUOz34QBuFALlw5fFOkg5lAbe6CY2JLltGN78yl0smfbvOxtIT5a8v8YlQzkt3JETQ 9mVLjhJx2QhuXcUg3Y1cistWgC7HRfFZme5TfG8URqDUHEtXktKT20H+iTRByTBBC5kv 3+aTligLoPsbvEV3jCjDKUsYYh44WAc2LXem0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=JcFZDYKObHz6OBsvfKoINkD0Qapg88Zw6PrYD9b2BHIIE5+/ZzaIXbuq5oA53F+wPa EcmLcpcL4i8HTKpT/RvKy1Qj6UeQCT+sPFTuWJ+ZhsG1vt4MwgY6uiWjdwbj0amFgNk5 DWUF0VNdNN1bP3kW8E1IIriWAd4d70/RPgQ8s= MIME-Version: 1.0 Received: by 10.102.215.19 with SMTP id n19mr481052mug.79.1249809191009; Sun, 09 Aug 2009 02:13:11 -0700 (PDT) In-Reply-To: References: Date: Sun, 9 Aug 2009 10:13:10 +0100 Message-ID: From: chris scott To: "John ." Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-questions@freebsd.org Subject: Re: a (hopefully) simple newbie zfs query regarding available space X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 09 Aug 2009 09:13:13 -0000 2009/8/9 John . > 2009/8/9 chris scott : > > > > > not a zfs thing is happens with all os and file systems. Basically HD > > manufacturers quote their capacities in base 10 ie 1 TB = 1000000000 > bytes. > > File systems are calculated in binary therefore the calculation they use > is > > 1024 x 1024 x 1024 = 1099511627776. Slightly more as you can see. > > > > Therefore 1 GB is os terms is 1073741824 > > > > therefore hd capacity in GB is > > > > 1000000000000/1073741824 = 931.322575 > > > > The extra you see is it due to HD manufactures slightly over capacity the > > drives > > > > Hi, > > What I meant was, I was seeing 931MB instead of 1.6TB (2x1TB disks) > but this was because I didn't read about zfs properly (they recommend > 3 or more disks. In the man page for zpool it says: > > "A raidz group with N disks of size X with P parity disks can hold > approximately (N-P)*X bytes > [...] > The recommended number is between 3 and 9" > > so, I'll wait till I get an array before implementing zfs. In the > meantime, I'm using gconcat. Sorry for the noise. > > -- > John > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " > freebsd-questions-unsubscribe@freebsd.org" > ah did you do a zpool create tank ad0 then zpool attach tank ad1 type thing? if you did you have you have created a mirror to fix do a zpool dettach ad1 then a zpool add ad1 to create a stripe Having said that it not good practice to have no redundancy. You could comprise by putting your important data on a dedicated file system then setting copies to 2 or 3