From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua0-f181.google.com ([209.85.217.181]:35634 "EHLO mail-ua0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729645AbeGaUVk (ORCPT ); Tue, 31 Jul 2018 16:21:40 -0400 Received: by mail-ua0-f181.google.com with SMTP id q12-v6so10972657ual.2 for ; Tue, 31 Jul 2018 11:40:04 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: From: Cerem Cem ASLAN Date: Tue, 31 Jul 2018 21:40:03 +0300 Message-ID: Subject: Re: Expected Received UUID To: Gaurav Sanghavi Cc: linux-btrfs@vger.kernel.org Content-Type: multipart/alternative; boundary="00000000000000506c05724fe8ca" Sender: linux-btrfs-owner@vger.kernel.org List-ID: --00000000000000506c05724fe8ca Content-Type: text/plain; charset="UTF-8" Not an answer, but exactly same case: https://unix.stackexchange.com/questions/377914/how-to-test-if-two-btrfs-snapshots-are-identical 2018-07-31 20:42 GMT+03:00 Gaurav Sanghavi : > Hello everyone, > > While researching BTRFS for a project that involves backing up snapshots > from device A to device B > before consolidating backups from device B to device C, I noticed that > received UUID on snapshot on > device C is not the same as received UUID for the same snapshot on device > B. Here are my steps: > > 1. Device A > BTRFS version: v3.17 > > btrfs su sn -r /home/test/snapshot1 /home/test/snaps/snapshot1 > btrfs su show /home/test/snaps/snapshot1 > Name: snapshot1 > uuid: b00e8ba1-5aaa-3641-9c4c-e168eee5c296 > Parent uuid: cb570dec-e9fd-1f40-99d2-2070c8ee2466 > Received UUID: --- > Creation time: 2018-07-30 18:32:37 > Flags: readonly > > 2. Send to Device B > btrfs send /home/test/snaps/snapshot1 | ssh 'btrfs receive > /home/backups/' > > After send completes, on Device B > BTRFS version: v4.7.3 > btrfs su show /home/backups/snapshot1 > Name: snapshot1 > UUID: 7c13d189-7fee-584e-ac90-e68cb0012f5c > Parent UUID: a2314f7c-4b11-ed40-901f-f1acb5ebf802 > Received UUID: b00e8ba1-5aaa-3641-9c4c-e168eee5c296 > Creation time: 2018-07-30 18:42:37 -0700 > Flags: readonly > > > 3. Send to Device C > btrfs send /home/backups/snapshot1 | ssh 'btrfs receive > /home/backups2/' > > After send completes, on Device C > BTRFS version: v4.7.3 > btrfs su show /home/backups2/snapshot1 > Name: snapshot1 > UUID: 8a13aab5-8e44-2541-9082-bc583933b964 > Parent UUID: 54e9b4ff-46dc-534e-b70f-69eb7bb21028 > Received UUID: 7c13d189-7fee-584e-ac90-e68cb0012f5c > Creation time: 2018-07-30 18:58:32 -0700 > Flags: readonly > > 1. I have gone through some of the archived emails and have noticed people > mentioning that > if received UUID is set, btrfs send propogates this 'received UUID'. But > in above case, > it's different for the same snapshot on all three devices. Is this the > expected behavior ? > > 2. We want to be able to start backing up from Device A to C, in case B > goes down or needs > to be replaced. If received UUID is expected to differ for the snapshot on > device B and C, incremental > backups will not work from A to C without setting received UUID. I have > seen python-btrfs > mentioned in a couple of emails; but have anyone of you used it in a > production environment ? > > This is my first post to this email. Please let me know if I am missing > any details. > > Thanks, > Gaurav > > --00000000000000506c05724fe8ca Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

2018-07-31 20:42 GMT+03:00 Gaurav Sanghavi= <gaurav.ms5@gmail.com>:
Hello everyone,=C2=A0

While researchi= ng BTRFS for a project that involves backing up snapshots from device A to = device B=C2=A0
before consolidating backups from device B to devi= ce C, I noticed that received UUID on snapshot on=C2=A0
device C = is not the same as received UUID for the same snapshot on device B. Here ar= e my steps:

1. Device A
BTRFS version: v= 3.17

btrfs su sn -r /home/test/snapshot1 /home= /test/snaps/snapshot1
btrfs su show /home/test/snaps/snapshot1
Name: snapshot1
uuid: = b00e8ba1-5aaa-3641-9c4c-e168eee5c296
Parent uuid: cb570dec-e9fd-1f40-99d2-2070c8ee2466
=C2=A0 = =C2=A0 =C2=A0 =C2=A0 Received UUID:=C2=A0 =C2=A0 =C2=A0 ---
Creation time: 2018-07-30 18:32:37
Flags: readonly

2. Send to Device B
= btrfs send /home/test/snaps/snapshot1 | ssh <device b> 'btrfs rec= eive /home/backups/'

After send completes,= on Device B
BTRFS version: v4.7.3
btrfs su show /home/= backups/snapshot1
Name: snapshot1
UUID: 7c13d189-7fee-584e-ac90-e68cb0012f5c
Parent UUID: a2314f7c-4b11-ed40-901f-f1acb5ebf802
Received UUID: b00e8ba1-5aaa-3641-9c4c-e168eee5c= 296
Creation time: <= span style=3D"white-space:pre-wrap"> 2018-07-30 18:42:37 -0700
Flags: readonly


<= /div>
3. Send to Device C
btrfs send /home/backups/snapshot1 = | ssh <device c> 'btrfs receive /home/backups2/'
After send completes, on Device C
BTRFS version: v4.= 7.3
btrfs su show /home/backups2/snapshot1
Name: snapshot1
UUID: 8a13aab5-8e44-254= 1-9082-bc583933b964
Parent UUID: 54e9b4ff-46= dc-534e-b70f-69eb7bb21028
Received UUID: 7c13= d189-7fee-584e-ac90-e68cb0012f5c
Creation time: 2018-07-30 18:58:32 -0700
Flags: readonly

1. I have gone through some of the arch= ived emails and have noticed people mentioning that
if received U= UID is set, btrfs send propogates this 'received UUID'. But in abov= e case,=C2=A0
it's different for the same snapshot on all thr= ee devices. Is this the expected behavior ?

2. We = want to be able to start backing up from Device A to C, in case B goes down= or needs=C2=A0
to be replaced. If received UUID is expected to d= iffer for the snapshot on device B and C, incremental
backups wil= l not work from A to C without setting received UUID. I have seen python-bt= rfs
mentioned in a couple of emails; but have anyone of you used = it in a production environment ?

This is my first = post to this email. Please let me know if I am missing any details.

Thanks,
Gaurav


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