From owner-freebsd-fs@freebsd.org Tue Jul 5 10:37:37 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 C19F1B21CEE for ; Tue, 5 Jul 2016 10:37:37 +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 5B59A1CB3 for ; Tue, 5 Jul 2016 10:37:37 +0000 (UTC) (envelope-from ben.rubson@gmail.com) Received: by mail-wm0-x229.google.com with SMTP id z126so70008416wme.0 for ; Tue, 05 Jul 2016 03:37:37 -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=LhEKewYLOfRMLOcpuOxDwuj3eGAsP3Ej/sLMOgieULQ=; b=LdKNcTPh7oaol0Wm4uAhu/zxdFDfos5O7Cyytc9x1sq/I+5ko6fSW2dJUuOidWXrSp fE8dV5sPBHgFXTSE3phn1bnTBTn1OAwXczdfyRsqpFqGs9Sh0n+RXna2hwMnszeqC55C HZagSnny2lScp503YvaHelLdpPIPuQEymNDDgtdryw1HPMrUOZZXAmFEGTfq8sU0jCb6 77/sWm3u6/90Gr525z+Whfi5k/ZkdKrpYPenlD19z5IGKtqnViZrypOOA9+qK6SJpmqQ E7IOIgumpNcjnbI+NX1IbVcLJyh+JzcER5AnduAVZY/J7l1bKr8ciwLQ/1gENCzLxOy4 5+Xg== 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=LhEKewYLOfRMLOcpuOxDwuj3eGAsP3Ej/sLMOgieULQ=; b=mvhl6WyizFy1ShQAQ7ahyRKCxCa87SUfAe7LN/IOWlQYBuhipAGg5Q7s4bXzkwbnPu K6X6JYWfoLmUTAUZXD+hS6xkmqNfMhxz8Q2SP69md0l6hmj2MV2J8+R4EIOmIGr38kaY vObndA2ronqnDV0wH61Oca+fKgWfR8I8jYNVc5aNOCFaAGNbg/0z/gL9/PTN3ya+sDMM MYz8cstZnQQ+MY0Kbwvz1llHO081NmjqZhxaJLoc9h5VCkEhZjdHqJMbdB4fUajBFZCK +9sAvBCCfXdhKEfnm6mGGDEK5aCugqOjxPZvz9tZ4r/kotaaQ+AwPjc4sb8k84u6kQw8 36Vw== X-Gm-Message-State: ALyK8tLveFJ6+Uym45N41uEiZ0trBmRJxYGrceb4yV4rlx62WUkbYhonaC5cOnAmpUvb1w== X-Received: by 10.194.112.161 with SMTP id ir1mr14676570wjb.118.1467715055351; Tue, 05 Jul 2016 03:37:35 -0700 (PDT) Received: from [192.168.1.16] (210.236.26.109.rev.sfr.net. [109.26.236.210]) by smtp.gmail.com with ESMTPSA id bh7sm1930508wjb.22.2016.07.05.03.37.34 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 05 Jul 2016 03:37:34 -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: Ben RUBSON In-Reply-To: <73DC3B93-60FF-4B20-AF80-5712F77818EF@ixsystems.com> Date: Tue, 5 Jul 2016 12:37:33 +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> <73DC3B93-60FF-4B20-AF80-5712F77818EF@ixsystems.com> 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: Tue, 05 Jul 2016 10:37:37 -0000 > On 04 Jul 2016, at 20:06, Jordan Hubbard wrote: >=20 >=20 >> 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 ? >=20 > Yes, of course. >=20 >> 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. >=20 > 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. Yep but SMART is not used by ZFS itself, according to a dev on #openzfs. There is however a feature request here : = https://github.com/zfsonlinux/zfs/issues/2777 I don't know whether FreeBSD iSCSI target implementation is SMART = pass-thru or not (I don't think so, my tests some months ago did not = work). However SMART data of iSCSI disks can easily be checked on the target = server itself (so not on the initiator, I agree) using smartmontools. > Drives also return checksum errors that may be masked by the iSCSI = target. Should be caught by smartmontools running on target, right ? > 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. At least FreeBSD implements persistent reservations : https://www.freebsd.org/cgi/man.cgi?query=3Dctl However I'm not sure ZFS itself uses such feature, which are more = relevant for clusters. Does it ? Ben