From owner-freebsd-fs@freebsd.org Mon Jul 4 18:06:37 2016 Return-Path: Delivered-To: freebsd-fs@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 035BAB91558 for ; Mon, 4 Jul 2016 18:06:37 +0000 (UTC) (envelope-from jkh@ixsystems.com) Received: from barracuda.ixsystems.com (barracuda.ixsystems.com [12.229.62.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.ixsystems.com", Issuer "Go Daddy Secure Certificate Authority - G2" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id D93712219 for ; Mon, 4 Jul 2016 18:06:36 +0000 (UTC) (envelope-from jkh@ixsystems.com) X-ASG-Debug-ID: 1467655595-08ca0410fd51d70001-3nHGF7 Received: from zimbra.ixsystems.com ([10.246.0.20]) by barracuda.ixsystems.com with ESMTP id FXssCJIzgJKF8ofn (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 04 Jul 2016 11:06:35 -0700 (PDT) X-Barracuda-Envelope-From: jkh@ixsystems.com X-Barracuda-RBL-Trusted-Forwarder: 10.246.0.20 X-ASG-Whitelist: Client Received: from localhost (localhost [127.0.0.1]) by zimbra.ixsystems.com (Postfix) with ESMTP id 7674ACA41D4; Mon, 4 Jul 2016 11:06:35 -0700 (PDT) Received: from zimbra.ixsystems.com ([127.0.0.1]) by localhost (zimbra.ixsystems.com [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id MiABdm9fTWbL; Mon, 4 Jul 2016 11:06:35 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by zimbra.ixsystems.com (Postfix) with ESMTP id 22BF3CA41E0; Mon, 4 Jul 2016 11:06:35 -0700 (PDT) X-Virus-Scanned: amavisd-new at ixsystems.com Received: from zimbra.ixsystems.com ([127.0.0.1]) by localhost (zimbra.ixsystems.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id I3335Gtf2c9R; Mon, 4 Jul 2016 11:06:35 -0700 (PDT) Received: from [172.20.0.34] (vpn.ixsystems.com [10.249.0.2]) by zimbra.ixsystems.com (Postfix) with ESMTPSA id CC94DCA41D4; Mon, 4 Jul 2016 11:06:34 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: HAST + ZFS + NFS + CARP From: Jordan Hubbard X-ASG-Orig-Subj: Re: HAST + ZFS + NFS + CARP In-Reply-To: Date: Mon, 4 Jul 2016 11:06:34 -0700 Cc: freebsd-fs@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: <73DC3B93-60FF-4B20-AF80-5712F77818EF@ixsystems.com> References: <20160630144546.GB99997@mordor.lan> <71b8da1e-acb2-9d4e-5d11-20695aa5274a@internetx.com> <20160630153747.GB5695@mordor.lan> <63C07474-BDD5-42AA-BF4A-85A0E04D3CC2@gmail.com> <678321AB-A9F7-4890-A8C7-E20DFDC69137@gmail.com> <20160630185701.GD5695@mordor.lan> To: Ben RUBSON X-Mailer: Apple Mail (2.3124) X-Barracuda-Connect: UNKNOWN[10.246.0.20] X-Barracuda-Start-Time: 1467655595 X-Barracuda-Encrypted: ECDHE-RSA-AES256-GCM-SHA384 X-Barracuda-URL: https://10.246.0.26:443/cgi-mod/mark.cgi X-Virus-Scanned: by bsmtpd at ixsystems.com X-Barracuda-BRTS-Status: 1 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 Jul 2016 18:06:37 -0000 > On Jul 1, 2016, at 11:23 AM, Ben RUBSON wrote: >=20 > Would you say that giving an iSCSI disk to ZFS hides some details of = the raw disk to ZFS ? Yes, of course. > I though that iSCSI would have been a totally "transparent" layer, = transferring all ZFS requests to the raw disk, giving back the answers, = hiding anything. Not really, no. There are other ways of talking to a disk or SSD = device, such as getting S.M.A.R.T. data to see when/if a drive is = failing. Drives also return checksum errors that may be masked by the = iSCSI target. Finally, there is SCSI-2 and there is SCSI-3 (where = things like persistent reservations are implemented). None of these = things are necessarily implemented by iSCSI. - Jordan