From owner-freebsd-fs@FreeBSD.ORG Mon Dec 8 09:36:38 2014 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 61598FEA for ; Mon, 8 Dec 2014 09:36:38 +0000 (UTC) Received: from mail-qc0-f170.google.com (mail-qc0-f170.google.com [209.85.216.170]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 1F82D672 for ; Mon, 8 Dec 2014 09:36:37 +0000 (UTC) Received: by mail-qc0-f170.google.com with SMTP id x3so3276327qcv.29 for ; Mon, 08 Dec 2014 01:36:31 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=/Hqhe+z8EhSlB8nG3IH8IZNqLKa2fAE+szq7UWS4jGI=; b=NBu4ZJmx/b2p91X+bv+U926S47vWj113Ve2yr58nyj8as20H1ifMbNPNF9/jN3Olej ptK7CC3hljjSeGh5MS1KyV4YHEl1B1+otsJF5RiVTyQBsOZd6i+sxePSiqwgA8O6wgBw yy6CW190rW3ex0so9Dtg494MRPDbDsFOG13eLAJ2ECR6AZ6joc3wkFQm5lPzpP1gtA3V GKtvqRsFWslfehCwgns64VPLhZzHvL8/1GOBgvFdh1fiFOUeaxW2InyBlXYGGs4c5l91 u2BXyR3uveb8yZqthOTIFe+DKhAn7Csim7EU74qkcbYH//WirZGDbaRkPbFb8vGjtm0U yvCA== X-Gm-Message-State: ALoCoQloo4lKzgaYoC5oBsmdVnTAyJgTNhWVTtnLwFfsC3VXRHqKgxnQVe0LNLzg+pJwtS3wTPnT MIME-Version: 1.0 X-Received: by 10.224.14.133 with SMTP id g5mr50403405qaa.81.1418031026889; Mon, 08 Dec 2014 01:30:26 -0800 (PST) Received: by 10.140.39.48 with HTTP; Mon, 8 Dec 2014 01:30:26 -0800 (PST) In-Reply-To: <5485681C.7010504@FreeBSD.org> References: <54825E70.20900@sorbs.net> <54842CC5.2020604@sorbs.net> <5485681C.7010504@FreeBSD.org> Date: Mon, 8 Dec 2014 02:30:26 -0700 Message-ID: Subject: Re: ZFS weird issue... From: Will Andrews To: Andriy Gapon Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 Cc: "freebsd-fs@freebsd.org" X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Dec 2014 09:36:38 -0000 On Monday, December 8, 2014, Andriy Gapon wrote: > > BTW, Will, don't you have a patch that help the vdev phys path to stay > up-to-date? > I don't believe we have any patch for a situation where a member disappears altogether. Perhaps the best we could do for a situation like this would be to wipe the physical path in the label for a faulted device, to reduce confusion. But a device that's been either manually offlined or physically removed could come back and be resilvered. There are patches to provide physical paths through SES/SAF-TE/SGPIO which offer paths decidedly more physical than a device name. And to perform automatic replacement by physical path based on these. Not sure to what degree these have been integrated in the mainline. But this still requires the system to have an enclosure service of some sort. Fundamentally, documentation should make clear which /dev device names are logical and can be reordered due to configuration changes (including device departure and arrival events) or reboots. As opposed to those based on immutable properties of the device. In the case of ZFS, the ideal physical path identifies a slot, so ZFS can detect when a particular member is being replaced at its physical location by a new device. So using a device's serial number is a little too specific for the job. But a typical logical device name is not specific enough. --Will.