From owner-freebsd-stable@freebsd.org Thu Jun 29 16:02:30 2017 Return-Path: Delivered-To: freebsd-stable@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 7BE2BDA03E5 for ; Thu, 29 Jun 2017 16:02:30 +0000 (UTC) (envelope-from asomers@gmail.com) Received: from mail-yw0-x22f.google.com (mail-yw0-x22f.google.com [IPv6:2607:f8b0:4002:c05::22f]) (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 3A72C64E55 for ; Thu, 29 Jun 2017 16:02:30 +0000 (UTC) (envelope-from asomers@gmail.com) Received: by mail-yw0-x22f.google.com with SMTP id j11so38817168ywa.2 for ; Thu, 29 Jun 2017 09:02:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=Clbu128eW21Ugaxs6BNpgjEokzskZu+bbSFSRQYRzKw=; b=BvydPcENKEc0Gx1qu2TTExiQKQXYdxfKxASHyeKt+XtmcBfo/+Ifwmy+Ohz6lDEJtG YV5PTNKoVH65lX8LCFXSQq9Wx+ITOAwCuVuMCtQqSSUNSt98YJ0+OwMudReByb4/NYw9 Cm6qi2FFh7kFw19UP/auKce1cb33ROggMEoVeCA9Up+ebKHIqHPw1oCuLk73jVQBbKNu n9R60etXC/SA9TRrnU5OpVpqB+tjRzerPNR3g3mTiWSqDdOgmnqtFMR7WPBIOsfB6SZz P/0JtdZmKhkPXB8gRtxn/M2kxottdcnivyTN3/n9EFLNmEbtHkNKr9MncbBGJXY0aMgr Kjfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=Clbu128eW21Ugaxs6BNpgjEokzskZu+bbSFSRQYRzKw=; b=e2Iv2fjm89MUzvYZ3MVhta4Oa9lTunKa0i93L/Mh+zsAY3/4u0fjFSkLuHxvJgg9Dk VhSwqOqKKTLYxc9gF0bH3q+GrHkDk2F8PhNZeuNeiB7Ywq9cI4EcAsePvSzilyo3Ydwb 6NjKK3h+VCK/mBzB8gqRINyYbhqhLqbWTESOMakrDtShT5JCxxliF7wtGrhLjBbo6hIE VhQnuFh5ese8WAhNsoPM6bzL5b/7W8H/CUCSmeMW2GLs5sYhiWDKGKygyGv1k5SkLTc4 Pi0v5KK1NanFDutuBrfikIqTjwz9rVigA2iotBeam/87gif+ZVhQzXJi2QFIjePM8ivJ 9J/w== X-Gm-Message-State: AKS2vOwCAFCD2/ar48dnHKttReL0OxmXVhDCevQNo6HvkYLNlQgLRH1U ZIF/q4grDr6j3w1siq51v6YDZZNaGQ== X-Received: by 10.13.235.202 with SMTP id u193mr12425337ywe.222.1498752149499; Thu, 29 Jun 2017 09:02:29 -0700 (PDT) MIME-Version: 1.0 Sender: asomers@gmail.com Received: by 10.13.206.199 with HTTP; Thu, 29 Jun 2017 09:02:28 -0700 (PDT) In-Reply-To: <2BF904CF-7EC1-41BC-A9F3-BFF7813A897D@punkt.de> References: <2BF904CF-7EC1-41BC-A9F3-BFF7813A897D@punkt.de> From: Alan Somers Date: Thu, 29 Jun 2017 10:02:28 -0600 X-Google-Sender-Auth: qnaL5shRptNkD0pvTKnnp3DeYWU Message-ID: Subject: Re: What is /dev/zfs? To: "Patrick M. Hausen" Cc: freebsd-stable Content-Type: text/plain; charset="UTF-8" X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 29 Jun 2017 16:02:30 -0000 On Thu, Jun 29, 2017 at 8:28 AM, Patrick M. Hausen wrote: > Hi, folks > > any pointer to an explanation would be nice, > there seems to be no zfs(4) manpage ... > > Reason for asking: I have a piece of software > that uses 14,000 ioctl() calls on that device during > one execution and I'm asking myself what it tries > to do. > > Thanks! > Patrick The zpool and zfs commands do everything through ioctls, and /dev/zfs is the device node those ioctls are bound to. You can't read from it or write to it; all you can with /dev/zfs is use ZFS's custom ioctls. -Alan