From owner-freebsd-questions@freebsd.org Wed Sep 9 15:17:15 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 9C971A00E3D for ; Wed, 9 Sep 2015 15:17:15 +0000 (UTC) (envelope-from wam@hiwaay.net) Received: from fly.hiwaay.net (fly.hiwaay.net [216.180.54.1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 683961CB7 for ; Wed, 9 Sep 2015 15:17:15 +0000 (UTC) (envelope-from wam@hiwaay.net) Received: from kabini1.local (dynamic-216-186-222-143.knology.net [216.186.222.143] (may be forged)) (authenticated bits=0) by fly.hiwaay.net (8.13.8/8.13.8/fly) with ESMTP id t89FHDcm002607 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO) for ; Wed, 9 Sep 2015 10:17:13 -0500 Subject: Re: Storage question To: freebsd-questions@freebsd.org 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> <20150909160005.d3b84775c3d0748014a871e5@sohara.org> From: "William A. Mahaffey III" Message-ID: <55F04D78.8070508@hiwaay.net> Date: Wed, 9 Sep 2015 10:22:42 -0453.75 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150909160005.d3b84775c3d0748014a871e5@sohara.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit 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 15:17:15 -0000 On 09/09/15 10:06, Steve O'Hara-Smith wrote: > 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. I have heard that filling your zpool is a *BAD* thing, but it can be for any FS, just maybe a bit worse for ZFS. I am going to study that option a bit more. The online docs all seem to show swap within the zpool as well, does that work OK, performance wise ? It would simplify installation, however I am planning to script that, so a bit of 'extra' effort for separate swap partitions is not an issue. I have always thought that separate swap partitions directly kernel managed were the best for swap performance if/when it gets down to that, no ? -- William A. Mahaffey III ---------------------------------------------------------------------- "The M1 Garand is without doubt the finest implement of war ever devised by man." -- Gen. George S. Patton Jr.