From owner-freebsd-questions@FreeBSD.ORG Tue Mar 24 05:09:45 2015 Return-Path: Delivered-To: freebsd-questions@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 F063C48C for ; Tue, 24 Mar 2015 05:09:45 +0000 (UTC) Received: from mail-oi0-f46.google.com (mail-oi0-f46.google.com [209.85.218.46]) (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 BBBAC8AD for ; Tue, 24 Mar 2015 05:09:45 +0000 (UTC) Received: by oier21 with SMTP id r21so159114029oie.1 for ; Mon, 23 Mar 2015 22:09:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:date:message-id:subject:from:to :content-type; bh=YaQevPVCIDGths6j8Jcx9RUUJClPIsi6cqRDDnHEVaw=; b=YWeS9dZrQnmrlTBHE2oD4whbxAPteD5mB6nHYshTFDj01cQR/S9o1HAxbMo6PAlBI7 ARj34QiGgPbGLyFpZgTeK5CRJYhEVOi/YuXRvPYkTrLDQkzUFtr/azOslpz3GNsaptr7 GltZXlSm6JpabxaMrTl1J2+hwd2X8aNBhX7us9RG04VLB7tnhT6Z2ZClLf5OtnJLjIL9 JR5UEKN6V6d/WRXS41UKahF5johzxOUldQhF/bSsz5u+j+7qXC7U5KpE7VM2XUVApVHM rhdRXHZB1BCPRhr6M574ClqjIHiFOC2ZpApd1cvVdm5uKr4zJBeVTTRsf97Gh9vdBY5t k/vQ== X-Gm-Message-State: ALoCoQmeLvIEo8lDTSEEWBPNdGAN6byTgekUOCmqGX7F1XmsCYShqJTfkdoQrVAB0q+0JMlY3uWu MIME-Version: 1.0 X-Received: by 10.202.218.135 with SMTP id r129mr1887090oig.26.1427173784571; Mon, 23 Mar 2015 22:09:44 -0700 (PDT) Received: by 10.182.60.226 with HTTP; Mon, 23 Mar 2015 22:09:44 -0700 (PDT) X-Originating-IP: [59.167.133.100] Date: Tue, 24 Mar 2015 16:09:44 +1100 Message-ID: Subject: Possible (or smart) to put freebsd-boot on USB stick for root-on-ZFS? From: Jason Birch To: "freebsd-questions@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Mar 2015 05:09:46 -0000 Hey there, I'm looking at a relatively old resource (https://wiki.freebsd.org/RootOnZFS/GPTZFSBoot/9.0-RELEASE) about how to run root on ZFS for 9.0, and I noticed the section on installing the boot section to all drives that make up the root. In my setup, I'll only be mirroring two SSDs on 10.1, but it made me consider the possibility of having the freebsd-boot partition on a USB stick rather than on each drive itself for basically the following reason: Should an SSD die, I'd need to say "boot from this other device" to get my system back up and running, do the original partitioning magic on the replacement device, get that back into the vdev... Should the USB stick die, I'd need to simply replace it with one that had the same image (that is, only the boot partition), and `zpool replace` a blank device (I won't have a swap partition). However, I can think of some downsides as well - namely that the USB stick is probably more likely to die than the SSDs, and that the image on the USB stick will change over time (This gets mounted as /boot? or am I mistaken here... This would plague the freebsd-boot on the SSDs as well, with drift...) Am I misinterpreting the point of freebsd-boot? Does /boot actually end up living on the ZFS mount, and freebsd-boot just contains enough information to read the kernel and other goodies required to bring up a full system from a ZFS dataset? Is my thought to use a USB stick for this partition a little thick or actually worth trying out? JB