From owner-freebsd-questions@freebsd.org Tue Dec 13 23:45:00 2016 Return-Path: Delivered-To: freebsd-questions@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 8C2A7C765C2 for ; Tue, 13 Dec 2016 23:45:00 +0000 (UTC) (envelope-from alexmiroslav@gmail.com) Received: from mail-vk0-x231.google.com (mail-vk0-x231.google.com [IPv6:2607:f8b0:400c:c05::231]) (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 4A2EE355 for ; Tue, 13 Dec 2016 23:45:00 +0000 (UTC) (envelope-from alexmiroslav@gmail.com) Received: by mail-vk0-x231.google.com with SMTP id w194so4154254vkw.2 for ; Tue, 13 Dec 2016 15:45:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:from:date:message-id:subject:to; bh=69ZxMIvrW3byx6r1AdSF63Hut5QoRmf4vUDsLToiZSU=; b=y8MNEYenkV7wUGpmrRE7Vu04IE4jKNP93nh3DCff8g/G/7j9DAFuyegBiP0EPuhSma Hm7fLdeimafVeW3NfvqfwV1OZP9WaNZZ5mM5nXiptKWU65oYFleVLNAABZYj5SZLeMDT Kmymbg610fIsC8oULCX2ogegmST3/tgXnDsEWUfn2jgsoGEP0vSei41djTQ2623fcxnX c9Q8IAJMpbQCP5yv8QNpW0X7OJ1mWly9gK2wtKvyxgx0t5XacjnSyPHfUPVsdWq6rseR kb/0eeifahNUiuagpzsKgxjOSfH8CMFs+67vPUETULBuwzKoOlsIKNgkNsmi2vDcW7Qp mlWQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=69ZxMIvrW3byx6r1AdSF63Hut5QoRmf4vUDsLToiZSU=; b=Gi4/ZedTa3Q6CgbxvDbJt3D2YLxWnfKXWkZ1Nna6R/07CL/ouOQCzH1/5ByPIqs35c cCSawGwDLpg4aY0w93VAUDGZMz5YBNtaG8178e/ayHT2ifjLNfjQc+b5uwxzMrLqMQ9v wktrtG3GPfAU4NhaGQUw2qs22ideqRsl+6zE5Jiqz+cVlJsLdMSZdAmBkpg11d1UPF3M A6pCpbFLH/JBPTXjz86qPMBvpkNSi0ql0fb+NdlQLaaBEkViShqXkvW9o0cGRVFMat7d SD9+U70ZIzsjtSVFLT/pO0E+lG0flzu0CZo73mJ+eWjgQ6GlLDcoG/LkFLhw5RsAal3G g8Kw== X-Gm-Message-State: AKaTC03/ZvFf/aGF2n5KycEy2fYUfiZbBbSEQJcZvFQr0VHTlMKSayFrtMaM8Qmh6O8k1boVZCc7piUUxczmwA== X-Received: by 10.176.7.8 with SMTP id h8mr71129660uah.114.1481672699214; Tue, 13 Dec 2016 15:44:59 -0800 (PST) MIME-Version: 1.0 Received: by 10.176.3.20 with HTTP; Tue, 13 Dec 2016 15:44:58 -0800 (PST) From: Aleksandr Miroslav Date: Tue, 13 Dec 2016 15:44:58 -0800 Message-ID: Subject: zfs (zxfer) replication -- "holes" in backups? To: freebsd-questions@freebsd.org Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.23 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 13 Dec 2016 23:45:00 -0000 I'm using zxfer to replicate my ZFS snapshot to another host. Occasionally, for whatever reason, zxfer can't replicate a particular snapshot. What I find is that later when zxfer tries again, it skips that snapshot it couldn't replicate and sends a newer one. This leaves the back up server with with a "hole", i. e. a missing snapshot. For example: I have server with the following snapshots: *zroot/usr/home@zfs-auto-snap_daily-2016-11-19-00h00 [EXISTS ON BACKUP]zroot/usr/home@zfs-auto-snap_weekly-2016-11-20-00h00 [EXISTS ON BACKUP]zroot/usr/home@zfs-auto-snap_daily-2016-11-21-00h00 [EXISTS ON BACKUP]zroot/usr/home@zfs-auto-snap_daily-2016-11-22-00h00 [EXISTS ON BACKUP]zroot/usr/home@zfs-auto-snap_daily-2016-11-23-00h00 [MISSING BACKUP][...]zroot/usr/home@zfs-auto-snap_hourly-2016-12-13-14h00 [MISSING BACKUP]zroot/usr/home@zfs-auto-snap_hourly-2016-12-13-15h00 [EXISTS ON BACKUP]* Here is my backup server: *zroot/usr/home@zfs-auto-snap_daily-2016-11-19-00h00* *zroot/usr/home@zfs-auto-snap_weekly-2016-11-20-00h00* *zroot/usr/home@zfs-auto-snap_daily-2016-11-21-00h00* *zroot/usr/home@zfs-auto-snap_daily-2016-11-22-00h00* *zroot/usr/home@zfs-auto-snap_hourly-2016-12-13-15h00* Notice that I have backups until the 22nd of November, and there is a huge gap until the 13th of December. Usually these gaps are small, one or two missing snapshots...in this particular case, the backup server was offline for a bit. When zxfer starts up again, I thought it would resume sending from the last one, it apparently doesn't do that. The way I have fixed this manually in the past is to delete the newest backup on the target server and run zxfer manually. Recently, the missing backups have gotten so large that this is somewhat painful to do. Is there something in zfs/zxfer I can change such that the backup server will always have the latest copy as the master? thanks, Alex