From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (ext-mx03.extmail.prod.ext.phx2.redhat.com [10.5.110.27]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u42DeLLC019742 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Mon, 2 May 2016 09:40:21 -0400 Received: from mhw.ulib.iupui.edu (mhw.ulib.iupui.edu [134.68.171.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 38F598111F for ; Mon, 2 May 2016 13:40:19 +0000 (UTC) Received: from mwood by mhw.ulib.iupui.edu with local (Exim 4.85) (envelope-from ) id 1axDjo-0004gi-T6 for linux-lvm@redhat.com; Mon, 02 May 2016 09:18:12 -0400 Date: Mon, 2 May 2016 09:18:12 -0400 From: "Mark H. Wood" Message-ID: <20160502131812.GA1949@IUPUI.Edu> References: <1714078834.3820492.1461944731537.JavaMail.yahoo.ref@mail.yahoo.com> <1714078834.3820492.1461944731537.JavaMail.yahoo@mail.yahoo.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="3V7upXqbjpZ4EhLz" Content-Disposition: inline In-Reply-To: <1714078834.3820492.1461944731537.JavaMail.yahoo@mail.yahoo.com> Subject: Re: [linux-lvm] about the lying nature of thin Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: To: linux-lvm@redhat.com --3V7upXqbjpZ4EhLz Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Apr 29, 2016 at 03:45:31PM +0000, matthew patton wrote: > > ~35GB each, meaning 35000 GB is available and 25000 is=20 > > in use, then it is not a lie to say to any individual customer: you can= =20 > > use 50GB if you want. >=20 > If enough of your so-called customers decide to use the space you promise= d them AND THAT THEY PAID FOR and instead they get massive data loss and ou= tages, you can bet your hiney they'll sue you silly. Executive summary: you shouldn't just take a wild guess and then turn your back on a thin-provisioned setup; you must understand your consumers and monitor your resources. It's reasonable in certain circumstances for a service provider to over-subscribe his hardware. He would be well advised to monitor actual allocation closely, to keep some cash or ready credit on hand for quick expansion of his real hardware, and to respond promptly by adding capacity when usage nears real hardware limits. He is taking a risk, betting that most customers won't max out their promised storage, and should manage that risk. Indeed, he should first gather statistics to understand the behavior of typical customers and determine whether he would be taking a *foolish* risk. Failure to adequately manage resources to redeem contracted promises is the provider's lie, not LVM's. Failure to plan is planning to fail. If that's too scary, don't use thin provisioning. --=20 Mark H. Wood Lead Technology Analyst University Library Indiana University - Purdue University Indianapolis 755 W. Michigan Street Indianapolis, IN 46202 317-274-0749 www.ulib.iupui.edu --3V7upXqbjpZ4EhLz Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iEYEABEIAAYFAlcnU5QACgkQs/NR4JuTKG8HCQCdGZzlQyElN310CGHjKaFLrCAO iVEAn2geUec9ARHbLGWI3GG4X5W/fTXQ =QcEv -----END PGP SIGNATURE----- --3V7upXqbjpZ4EhLz--