From owner-freebsd-fs@freebsd.org Fri Jul 1 18:23:58 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 D4E3EB8F517 for ; Fri, 1 Jul 2016 18:23:58 +0000 (UTC) (envelope-from ben.rubson@gmail.com) Received: from mail-wm0-x229.google.com (mail-wm0-x229.google.com [IPv6:2a00:1450:400c:c09::229]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 6769328F2 for ; Fri, 1 Jul 2016 18:23:58 +0000 (UTC) (envelope-from ben.rubson@gmail.com) Received: by mail-wm0-x229.google.com with SMTP id a66so39786704wme.0 for ; Fri, 01 Jul 2016 11:23:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:subject:from:in-reply-to:date :content-transfer-encoding:message-id:references:to; bh=gCwMibvWJKs5cYUkO6Gr93C0gw1V5mEsComlCo+QkYE=; b=Kf+tP5BnfGJxr5DN4/CJk9BMeF0D33FFaZZ7PkLGQeELMCeB9U4r3tE5gFUWtR+0jQ dKWMKMIRtj0WB5c6QTcMUTxYcxj6sAxgDR9v+FshR0mrNeLBCBNigqRYZ29qA4hVxoKf 6BsHgcMoBiATyxIXDIU2nBp7koMTn0wot8qMy47jBBaT2N0nJfRMlBIC4ADiqj2fPpVr ZPCIPF6+myqrzKNLFXdIrzLQb9/g7v25XGy6ag+JintNijCO4+QP2J6vAq8nUQOsr3FP r59PKRsRz14Y9VxNowT5nNcLE0n1BGSGqSs6bvxuoH1tgD5TT8h4EpY3fhDK/O1Hb5NF hQlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date :content-transfer-encoding:message-id:references:to; bh=gCwMibvWJKs5cYUkO6Gr93C0gw1V5mEsComlCo+QkYE=; b=gvTn4RQg23M61OB6km2nP4CKlA++DPAFLzAhb2rTtfOU+Ja9pb2Z0W8DCbquhGOBKE iBWLg3Dbg5FVJp1r3/vJG5beha+cgHaMiRz1WoJfNi9gd+aM3hrP/0C24zDkzxVDc7n+ 0273ocOAEY98hcvr0QhIZ6rdg0XnJPmIjkpsby/DFX3IcX8vMw1ZG04WhRbeecBJmw5l bJITwcVszD/qGa1dQGMJeAgsvcQuBHogY2oUxrUiH9m+sY8mUKLbFo2/8CeN3xThLh6f /7bUNb5eATth1fYhzTDKmkjAs/slTddB+J1uX8VkAu/hI3ThEaKFAdE5GiFDlhCvr7Xo HFIg== X-Gm-Message-State: ALyK8tLalLBhEWGzsiB26Nt/KtQ9UG3ADD6p6kB/05hipMUOB5D8+d9IEhbkGvstO9ZaVA== X-Received: by 10.194.145.244 with SMTP id sx20mr5463983wjb.169.1467397436727; Fri, 01 Jul 2016 11:23:56 -0700 (PDT) Received: from macbook-air-de-benjamin-1.home (LFbn-1-7077-85.w90-116.abo.wanadoo.fr. [90.116.246.85]) by smtp.gmail.com with ESMTPSA id q63sm3661921wma.0.2016.07.01.11.23.55 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 01 Jul 2016 11:23:55 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: HAST + ZFS + NFS + CARP From: Ben RUBSON In-Reply-To: Date: Fri, 1 Jul 2016 20:23:54 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: 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: freebsd-fs@freebsd.org X-Mailer: Apple Mail (2.3124) 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: Fri, 01 Jul 2016 18:23:58 -0000 > On 01 Jul 2016, at 19:54, Jordan Hubbard wrote: > (...) > And yes, of course one can layer additional things on top of iSCSI = LUNs, just as one can punch through LUNs from older SAN fabrics and put = ZFS pools on top of them (been there, done both of those things), though = of course the additional indirection has performance and debugging = ramifications of its own (when a pool goes sideways, you have additional = things in the failure chain to debug). ZFS really likes to =E2=80=9Cown = the disks=E2=80=9D in terms of providing block-level fault tolerance and = predictable performance characteristics given specific vdev topologies, = and once you start abstracting the disks away from it, making statements = about predicted IOPs for the pool becomes something of a =E2=80=9C???=E2=80= =9D exercise. Would you say that giving an iSCSI disk to ZFS hides some details of the = raw disk to ZFS ? 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. As you experienced iSCSI, any sad story with iSCSI disks given to ZFS ? Many thanks for your long feedback Jordan !