From owner-freebsd-questions@freebsd.org Wed Sep 9 15:00:08 2015 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 7345FA00480 for ; Wed, 9 Sep 2015 15:00:08 +0000 (UTC) (envelope-from steve@sohara.org) Received: from uk1rly2283.eechost.net (relay01.mail.uk1.eechost.net [217.69.40.69]) by mx1.freebsd.org (Postfix) with ESMTP id 1BDC81259 for ; Wed, 9 Sep 2015 15:00:08 +0000 (UTC) (envelope-from steve@sohara.org) Received: from [88.151.27.41] (helo=smtp.marelmo.com) by uk1rly2283.eechost.net with esmtpa (Exim 4.72) (envelope-from ) id 1ZZgr0-0000fX-NB for freebsd-questions@freebsd.org; Wed, 09 Sep 2015 16:00:06 +0100 Received: from [192.168.63.1] (helo=steve.lan.sohara.org) by smtp.marelmo.com with smtp (Exim 4.85 (FreeBSD)) (envelope-from ) id 1ZZgqz-000OeD-U6 for freebsd-questions@freebsd.org; Wed, 09 Sep 2015 15:00:06 +0000 Date: Wed, 9 Sep 2015 16:00:05 +0100 From: Steve O'Hara-Smith To: freebsd-questions@freebsd.org Subject: Re: Storage question Message-Id: <20150909160005.d3b84775c3d0748014a871e5@sohara.org> In-Reply-To: <55F0451A.5080709@hiwaay.net> References: <55EF3D23.5060009@hiwaay.net> <20150908220639.20412cbd@gumby.homeunix.com> <55EF5409.8020007@yahoo.com> <55EFC2DA.3020101@hiwaay.net> <08B351DD-AA48-4F30-B0D6-C500D0877FB3@lafn.org> <55F02DC8.7000706@hiwaay.net> <20150909150626.5c3b99e5.freebsd@edvax.de> <55F031A0.40500@hiwaay.net> <20150909145820.c3b48aafad4f70553c1c1fd8@sohara.org> <55F0451A.5080709@hiwaay.net> X-Mailer: Sylpheed 3.4.3 (GTK+ 2.24.28; amd64-portbld-freebsd10.1) X-Clacks-Overhead: "GNU Terry Pratchett" Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Auth-Info: 24227@permanet.ie (plain) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Sep 2015 15:00:08 -0000 On Wed, 9 Sep 2015 09:47:00 -0453.75 "William A. Mahaffey III" wrote: > On 09/09/15 09:04, Steve O'Hara-Smith wrote: > > On Wed, 9 Sep 2015 08:23:54 -0453.75 > > "William A. Mahaffey III" wrote: > > > >> I like ZFS in principal (it's one of the things that attracted me to > >> FreeBSD about a year ago), but, as someone else noted, it seems to > >> require lots of RAM & possibly CPU for best effect. The MythTV box is > >> an AMD A4-5000, 1.5 GHz quad-core jaguar, w/ 16 GB of RAM, which isn't > > My house fileserver (erm NAS in modern speak) is a dual core > > Atom with 4GB. It manages a 4x2TB RAIDZ2 as well as a bunch of jails. > > According to top it has 2432M for ARC (3592M altogether is wired). > > Memory is tight but it's not swapping, and it doesn't no matter what > > the load. Switching to your spec would be a hefty upgrade and would > > almost certainly make things faster, but then most things can be made > > faster with an extra expenditure. > > > >> especially robusto by today's standards, so I am staying w/ UFS. > >> Someone > > If you have the opportunity then benchmark ZFS and see, if you > > can run it the benefits are great. > > > > I am quite amenable to running ZFS, I just don't want to have to abandon > it & return to UFS if my system proves inadequate for the task, hence my > caution about it. If I go to ZFS, I (*think* I) use it for the whole > drives, except for swap (possibly), & slice it up into > 'partitions/slices/whatever' to do the install, right ? That was my > take-away from reading the online pages about it. Maybe I need to > rethink .... Yes that's essentially it - you assemble the raw storage you're going to use into a zpool from which the storage that backs the filesystems is drawn automatically. Once you have a zpool making a filesystem is very cheap. The filesystems share the pool, if you want to cap them you can but otherwise they're all limited by the pool. I've never filled a ZFS pool, I don't think I want to. -- Steve O'Hara-Smith