From owner-freebsd-current@FreeBSD.ORG Wed Oct 1 18:09:33 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id D50ECCA5; Wed, 1 Oct 2014 18:09:33 +0000 (UTC) Received: from h2.funkthat.com (gate2.funkthat.com [208.87.223.18]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "funkthat.com", Issuer "funkthat.com" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 959C7EB9; Wed, 1 Oct 2014 18:09:33 +0000 (UTC) Received: from h2.funkthat.com (localhost [127.0.0.1]) by h2.funkthat.com (8.14.3/8.14.3) with ESMTP id s91I9WKw062788 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 1 Oct 2014 11:09:32 -0700 (PDT) (envelope-from jmg@h2.funkthat.com) Received: (from jmg@localhost) by h2.funkthat.com (8.14.3/8.14.3/Submit) id s91I9Wjt062787; Wed, 1 Oct 2014 11:09:32 -0700 (PDT) (envelope-from jmg) Date: Wed, 1 Oct 2014 11:09:32 -0700 From: John-Mark Gurney To: Allan Jude Subject: Re: zpool frag Message-ID: <20141001180932.GA43300@funkthat.com> Mail-Followup-To: Allan Jude , freebsd-current@freebsd.org References: <1411289830171-5950788.post@n5.nabble.com> <541EE962.2000801@freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <541EE962.2000801@freebsd.org> User-Agent: Mutt/1.4.2.3i X-Operating-System: FreeBSD 7.2-RELEASE i386 X-PGP-Fingerprint: 54BA 873B 6515 3F10 9E88 9322 9CB1 8F74 6D3F A396 X-Files: The truth is out there X-URL: http://resnet.uoregon.edu/~gurney_j/ X-Resume: http://resnet.uoregon.edu/~gurney_j/resume.html X-TipJar: bitcoin:13Qmb6AeTgQecazTWph4XasEsP7nGRbAPE X-to-the-FBI-CIA-and-NSA: HI! HOW YA DOIN? can i haz chizburger? X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.2 (h2.funkthat.com [127.0.0.1]); Wed, 01 Oct 2014 11:09:32 -0700 (PDT) Cc: freebsd-current@freebsd.org X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 01 Oct 2014 18:09:33 -0000 Allan Jude wrote this message on Sun, Sep 21, 2014 at 11:06 -0400: > On 2014-09-21 04:57, Beeblebrox wrote: > > FRAG means fragmentation, right? Zpool fragmentation? That's news to me. If > > this is real how do I fix it? > > > > NAME SIZE ALLOC FREE FRAG EXPANDSZ CAP DEDUP HEALTH ALTROOT > > pool1 75.5G 53.7G 21.8G 60% - 71% 1.00x ONLINE - > > pool2 48.8G 26.2G 22.6G 68% - 53% 1.00x ONLINE - > > pool3 204G 177G 27.0G 53% - 86% 1.11x ONLINE - > > > > Regards. > > > > > > > > ----- > > FreeBSD-11-current_amd64_root-on-zfs_RadeonKMS > > -- > > View this message in context: http://freebsd.1045724.n5.nabble.com/zpool-frag-tp5950788.html > > Sent from the freebsd-current mailing list archive at Nabble.com. > > _______________________________________________ > > freebsd-current@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/freebsd-current > > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" > > > > It is not something you 'fix', it is just a metric to help you > understand the performance of your pool. The higher the fragmentation, > the longer it might take to allocate new space, and obviously you will > have more random seek time while reading from the pool. > > As Steven mentions, there is no defragmentation tool for ZFS. You can > zfs send/recv or backup/restore the pool if you have a strong enough > reason to want to get the fragmentation number down. > > It is a fairly natural side effect of a copy-on-write file system. > > Note: the % is not the % fragmented, IIRC, it is the percentage of the > free blocks that are less that a specific size. I forget what that size is. Can we get this documented in the zpool man page? I assume that the FRAG is the same as: fragmentation The amount of fragmentation in the pool. and that description is woefully lacking.. -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."