From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f50.google.com ([209.85.215.50]:43448 "EHLO mail-lf0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750711AbdIREXX (ORCPT ); Mon, 18 Sep 2017 00:23:23 -0400 Received: by mail-lf0-f50.google.com with SMTP id c80so6696799lfh.0 for ; Sun, 17 Sep 2017 21:23:23 -0700 (PDT) Subject: Re: ERROR: parent determination failed (btrfs send-receive) To: Dave , linux-btrfs@vger.kernel.org References: From: Andrei Borzenkov Message-ID: <1fa167f4-a8ba-84c7-8e06-9c7e9f3d30e7@gmail.com> Date: Mon, 18 Sep 2017 07:23:20 +0300 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: 18.09.2017 05:31, Dave пишет: > Sometimes when using btrfs send-receive, I get errors like this: > > ERROR: parent determination failed for > > When this happens, btrfs send-receive backups fail. And all subsequent > backups fail too. > > The issue seems to stem from the fact that an automated cleanup > process removes certain earlier subvolumes. (I'm using Snapper.) > > I'd like to understand exactly what is happening so that my backups do > not unexpectedly fail. > You try to send incremental changes but you deleted subvolume to compute changes against. It is hard to tell more without seeing subvolume list with uuid/parent uuid. > In my scenario, no parent subvolumes have been deleted from the > target. Some subvolumes have been deleted from the source, but why > does that matter? I am able to take a valid snapshot at this time and > every snapshot ever taken continues to reside at the target backup > destination (seemingly meaning that a parent subvolume can be found at > the target). > > This issue seems to make btrfs send-receive a very fragile backup > solution. btrfs send/receive is not backup solution - it is low level tool that does exactly what it is told to do. You may create backup solution that is using btrfs send/receive to transfer data stream, but then do not blame tool for incorrect usage. To give better advice how to fix your situation you need to describe your backup solution - how exactly you select/create snapshots. I hope, instead, there is some knowledge I'm missing, that > when learned, will make this a robust backup solution. > > Thanks > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >