From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f48.google.com ([209.85.214.48]:33400 "EHLO mail-it0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751112AbdDYECQ (ORCPT ); Tue, 25 Apr 2017 00:02:16 -0400 Received: by mail-it0-f48.google.com with SMTP id 70so17751942ita.0 for ; Mon, 24 Apr 2017 21:02:16 -0700 (PDT) Received: from [192.168.0.23] ([98.4.97.1]) by smtp.gmail.com with ESMTPSA id s40sm875161ite.18.2017.04.24.21.02.14 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 24 Apr 2017 21:02:14 -0700 (PDT) Message-ID: <58FECA45.1010107@gmail.com> Date: Tue, 25 Apr 2017 00:02:13 -0400 From: "J. Hart" Reply-To: jfhart085@gmail.com MIME-Version: 1.0 To: linux-btrfs@vger.kernel.org Subject: backing up a collection of snapshot subvolumes Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: I have a remote machine with a filesystem for which I periodically take incremental snapshots for historical reasons. These snapshots are stored in an archival filesystem tree on a file server. Older snapshots are removed and newer ones added on a rotational basis. I need to be able to backup this archive by syncing it with a set of backup drives. Due to the size, I need to back it up incrementally rather than sending the entire content each time. Due to the snapshot rotation, I need to be able to update the state of the archive backup filesystem as a whole, in much the same manner that rsync handles file trees. It seems that I cannot use "btrfs send", as the archive directory contains the snapshots as subvolumes. I cannot use rsync as it treats subvolumes as simple directories, and does not preserve subvolume attributes. Rsync also does not support reflinks, so the snapshot directory content will no longer be reflinked to other snapshots on the archive backup. I cannot use hard links in the incrementals as hard links do not cross subvolume boundaries. Thoughts anyone ?