From owner-freebsd-fs@freebsd.org Mon Oct 21 05:50:37 2019 Return-Path: Delivered-To: freebsd-fs@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 835D71745EA for ; Mon, 21 Oct 2019 05:50:37 +0000 (UTC) (envelope-from gerrit.kuehn@aei.mpg.de) Received: from mailgate2.uni-hannover.de (mailgate2.uni-hannover.de [130.75.2.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 46xQj84WGyz3J5w for ; Mon, 21 Oct 2019 05:50:36 +0000 (UTC) (envelope-from gerrit.kuehn@aei.mpg.de) Received: from intranet.aei.uni-hannover.de (ahin1.aei.uni-hannover.de [130.75.117.40]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mailgate2.uni-hannover.de (Postfix) with ESMTPS id 1D6E6C63 for ; Mon, 21 Oct 2019 07:50:34 +0200 (CEST) Received: from arc.aei.uni-hannover.de ([130.75.117.1]) by intranet.aei.uni-hannover.de (IBM Domino Release 9.0.1FP8) with ESMTP id 2019102107503384-8605 ; Mon, 21 Oct 2019 07:50:33 +0200 Date: Mon, 21 Oct 2019 07:50:33 +0200 From: Gerrit =?UTF-8?B?S8O8aG4=?= To: freebsd-fs@freebsd.org Subject: Re: zfs capacity Message-ID: <20191021075033.6c9748c7@arc.aei.uni-hannover.de> In-Reply-To: <20191018113554.4f5822e3@arc.aei.uni-hannover.de> References: <20191018113554.4f5822e3@arc.aei.uni-hannover.de> Organization: Albert-Einstein-Institut X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; amd64-portbld-freebsd11.2) MIME-Version: 1.0 X-MIMETrack: Itemize by SMTP Server on intranet/aei-hannover(Release 9.0.1FP8|February 23, 2017) at 21/10/2019 07:50:33, Serialize by Router on intranet/aei-hannover(Release 9.0.1FP8|February 23, 2017) at 21/10/2019 07:50:34, Serialize complete at 21/10/2019 07:50:34 X-TNEFEvaluated: 1 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 X-Rspamd-Queue-Id: 46xQj84WGyz3J5w X-Spamd-Bar: - Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=none (mx1.freebsd.org: domain of gerrit.kuehn@aei.mpg.de has no SPF policy when checking 130.75.2.114) smtp.mailfrom=gerrit.kuehn@aei.mpg.de X-Spamd-Result: default: False [-1.10 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-0.91)[-0.909,0]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-0.91)[-0.906,0]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-fs@freebsd.org]; TO_DN_NONE(0.00)[]; AUTH_NA(1.00)[]; RCPT_COUNT_ONE(0.00)[1]; HAS_ORG_HEADER(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; DMARC_NA(0.00)[mpg.de]; RCVD_IN_DNSWL_MED(-0.20)[114.2.75.130.list.dnswl.org : 127.0.11.2]; R_SPF_NA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:680, ipnet:130.75.0.0/16, country:DE]; RCVD_TLS_LAST(0.00)[]; IP_SCORE(0.02)[asn: 680(0.11), country: DE(-0.01)] X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Oct 2019 05:50:37 -0000 Am Fri, 18 Oct 2019 11:35:54 +0200 schrieb Gerrit K=C3=BChn : Hi, > I just tried these two raidz2 setups with 36 disks: 3x 10+2, 4x 7+2. > The result is a bit puzzling for me, because I get the same capacity, > although one setup is using 6 drives for redundancy, the other is using > 8: For the record: I found this to be caused by allocation padding (and I was most irritated by the fact that in the case I tested it turned out to yield /exactly/ the same number of usable space regardless of having two more data disks). Anyway, I found this table very helpful, so I'd like to share the link (even if this may be well-known to others already, it took me some time to find it): cu Gerrit