Your message dated Mon, 21 Nov 2016 23:05:05 +0100
with message-id <[email protected]>
and subject line Closing, no response
has caused the Debian Bug report #557817,
regarding nbd has I/O errors with md-over-dmcrypt-over-nbd
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
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--
557817: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=557817
Debian Bug Tracking System
Contact [email protected] with problems
--- Begin Message ---
Package: nbd-client
Version: 1:2.9.14-1
Severity: normal
I am trying to investigate a remote backup solution: nbd-server
gives me a block device from remote, which I locally crypt with
dmcrypt, and then use as a component of a RAID1. The backups are
written to the RAID1, and by rsync'ing the RAID, I effectively
generate an encrypted live-backup remotely.
Unfortunatly, that is only the theory, for in practice, the
dmcrypt+nbd combination doesn't seem to work (it might well be
a dmcrypt problem, though not likely):
% dd if=/dev/zero of=nbd-file bs=1M count=1 seek=1023
1+0 records in
1+0 records out
1048576 bytes (1.0 MB) copied, 0.00447344 s, 234 MB/s
% nbd-server 127.0.0.1:12345 `pwd`/nbd-file 1024M -C/dev/null
% netstat -natp | grep :12345
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
tcp 0 0 127.0.0.1:12345 0.0.0.0:* LISTEN
16385/nbd-server
% sudo nbd-client localhost 12345 /dev/nbd0
Negotiation: ..size = 1048576KB
bs=1024, sz=1048576
% echo foo > key
% sudo cryptsetup luksFormat /dev/nbd0 ./key
WARNING!
========
This will overwrite data on /dev/nbd0 irrevocably.
Are you sure? (Type uppercase yes): YES
% grep nbd /var/log/syslog | tail
Nov 24 17:24:37 piper nbd_server[16385]: connect from 127.0.0.1, assigned
file is /home/madduck/.tmp/cdt.hPOcvv/nbd-file
Nov 24 17:24:37 piper nbd_server[16385]: Can't open authorization file
/etc/nbd-server/allow (No such file or directory).
Nov 24 17:24:37 piper nbd_server[16385]: Authorized client
Nov 24 17:24:37 piper nbd_server[16405]: Starting to serve
Nov 24 17:24:37 piper nbd_server[16405]: Size of exported file/device is
1073741824
Nov 24 17:24:37 piper kernel: [537982.733434] nbd0: unknown partition table
% sudo cryptsetup luksOpen -d ./key /dev/nbd0 cryptnbd
Key slot 0 unlocked.
% dd if=/dev/zero of=loop-file bs=1M count=1 seek=1023
1+0 records in
1+0 records out
1048576 bytes (1.0 MB) copied, 0.00413988 s, 253 MB/s
% sudo losetup -vf ./loop-file
Loop device is /dev/loop0
% sudo mdadm -Cl1 -n2 -ayes /dev/md99 /dev/mapper/cryptnbd /dev/loop0
mdadm: array /dev/md99 started.
% cat /proc/mdstat
Personalities : [raid1]
md99 : active (auto-read-only) raid1 loop0[1] dm-7[0]
1047936 blocks [2/2] [UU]
resync=PENDING
unused devices: <none>
So far so good. Now as soon as I write anything to the array, it will start
sync'ing. And this is when the I/O errors start, but the RAID syncs fine
actually.
% tail -f /var/log/syslog | grep nbd&
[1] 17024 17025
% dd if=/dev/zero of=/dev/md99 bs=1 count=1
dd: opening `/dev/md99': Permission denied
% sudo dd if=/dev/zero of=/dev/md99 bs=1 count=1
1+0 records in
1+0 records out
1 byte (1 B) copied, 0.0993314 s, 0.0 kB/s
Nov 24 17:41:45 piper kernel: [539010.683028] end_request: I/O error, dev
nbd0, sector 0
[…] (34 in between)
Nov 24 17:42:41 piper kernel: [539066.182929] md: md99: resync done.
Nov 24 17:42:41 piper kernel: [539066.212929] end_request: I/O error, dev
nbd0, sector 0
Nov 24 17:42:41 piper kernel: [539066.435511] end_request: I/O error, dev
nbd0, sector 0
Nov 24 17:42:43 piper mdadm[2599]: RebuildFinished event detected on md
device /dev/md99
Nov 24 17:42:43 piper kernel: [539068.098878] RAID1 conf printout:
Nov 24 17:42:43 piper kernel: [539068.098883] --- wd:2 rd:2
Nov 24 17:42:43 piper kernel: [539068.098887] disk 0, wo:0, o:1, dev:dm-7
Nov 24 17:42:43 piper kernel: [539068.098891] disk 1, wo:0, o:1, dev:loop0
Nov 24 17:42:43 piper kernel: [539068.099206] end_request: I/O error, dev
nbd0, sector 0
% cat /proc/mdstat
Personalities : [raid1]
md99 : active raid1 loop0[1] dm-7[0]
1047936 blocks [2/2] [UU]
976510912 blocks [2/2] [UU]
unused devices: <none>
Subsequently, I can read the entire array (I tried with dd) without
any further I/O errors, but when I write to it, the I/O errors
re-appear.
The problem only appears when dmcrypt is in between nbd and md, not
if I use /dev/nbd0 directly for the RAID1.
Thus this problem might well be with dmcrypt, but it's unlikely.
I tried the same setup with a loop device instead of nbd (loop0
directly, dmcrypt-on-loop1, RAID1 across loop0 and dmcrypt device),
and there were no I/O errors.
-- System Information:
Debian Release: squeeze/sid
APT prefers unstable
APT policy: (500, 'unstable'), (500, 'testing'), (1, 'experimental')
Architecture: amd64 (x86_64)
Kernel: Linux 2.6.31-1-amd64 (SMP w/1 CPU core)
Locale: LANG=en_GB, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Versions of packages nbd-server depends on:
ii adduser 3.111 add and remove users and groups
ii debconf [debconf-2.0] 1.5.28 Debian configuration management sy
ii libc6 2.10.1-7 GNU C Library: Shared libraries
ii libglib2.0-0 2.22.2-2 The GLib library of C routines
ii ucf 3.0025 Update Configuration File: preserv
nbd-server recommends no packages.
nbd-server suggests no packages.
-- debconf information excluded
--
.''`. martin f. krafft <[email protected]> Related projects:
: :' : proud Debian developer http://debiansystem.info
`. `'` http://people.debian.org/~madduck http://vcs-pkg.org
`- Debian - when you have better things to do than fixing systems
digital_signature_gpg.asc
Description: Digital signature (see http://martin-krafft.net/gpg/)
--- End Message ---
--- Begin Message ---
A request for reproducibility did not produce a response in over 6 years, so
closing.
--
< ron> I mean, the main *practical* problem with C++, is there's like a dozen
people in the world who think they really understand all of its rules,
and pretty much all of them are just lying to themselves too.
-- #debian-devel, OFTC, 2016-02-12
--- End Message ---
