Months ago, I worked on a NULL pointer deference crash on dm mirror
target. I worked out two patches
to fix the crash issue, but when I was submitting them, I found that
upstream had "fixed" the crash by
reverting, you can find the discussion here:
- https://patchwork.kernel.org/patch/9808897/
Zdenek did through out his doubt, but no body gave response:
"""
Which kernel version is this ?
I'd thought we've already fixed this BZ for old mirrors:
https://bugzilla.redhat.com/show_bug.cgi?id=1382382
There similar BZ for md-raid based mirrors (--type raid1)
https://bugzilla.redhat.com/show_bug.cgi?id=1416099
My base kernel version is 4.4.68, but with this 2 latest fixes applied:
"""
Revert "dm mirror: use all available legs on multiple failures"
Ohh - I've -rc6 - while this 'revert' patch went to 4.12-rc7.
I'm now starting to wonder why?
It's been a real fix for a real issue - and 'revert' message states
there is no such problem ??
I'm confused....
Mike - have you tried the sequence from BZ ?
Zdenek
"""
I wrongly accepted the facts:
1. the crash issue do disappear;
2. the "reverting" fixing way is likely wrong, but I did follow up it
further because
people now mainly uses raid1 instead of mirror - my fault to think that
way.
But, I was just feeling it's hard to persuade the maintainer to revert
the "reverting fixes"
and try my fix.
Anyway, why are you using mirror? why not raid1?
Eric
On 02/05/2018 03:42 PM, Liwei wrote:
Hi Eric,
Thanks for answering! Here are the details:
# lvm version
LVM version: 2.02.176(2) (2017-11-03)
Library version: 1.02.145 (2017-11-03)
Driver version: 4.37.0
Configuration: ./configure --build=x86_64-linux-gnu --prefix=/usr
--includedir=${prefix}/include --mandir=${prefix}/share/man
--infodir=${prefix}/share/info --sysconfdir=/etc --localstatedir=/var
--disable-silent-rules --libdir=${prefix}/lib/x86_64-linux-gnu
--libexecdir=${prefix}/lib/x86_64-linux-gnu --runstatedir=/run
--disable-maintainer-mode --disable-dependency-tracking --exec-prefix=
--bindir=/bin --libdir=/lib/x86_64-linux-gnu --sbindir=/sbin
--with-usrlibdir=/usr/lib/x86_64-linux-gnu --with-optimisation=-O2
--with-cache=internal --with-clvmd=corosync --with-cluster=internal
--with-device-uid=0 --with-device-gid=6 --with-device-mode=0660
--with-default-pid-dir=/run --with-default-run-dir=/run/lvm
--with-default-locking-dir=/run/lock/lvm --with-thin=internal
--with-thin-check=/usr/sbin/thin_check
--with-thin-dump=/usr/sbin/thin_dump
--with-thin-repair=/usr/sbin/thin_repair --enable-applib
--enable-blkid_wiping --enable-cmdlib --enable-cmirrord
--enable-dmeventd --enable-dbus-service --enable-lvmetad
--enable-lvmlockd-dlm --enable-lvmlockd-sanlock --enable-lvmpolld
--enable-notify-dbus --enable-pkgconfig --enable-readline
--enable-udev_rules --enable-udev_sync
# uname -a
Linux dataserv 4.14.0-3-amd64 #1 SMP Debian 4.14.13-1 (2018-01-14)
x86_64 GNU/Linux
Warm regards,
Liwei
On 5 Feb 2018 15:27, "Eric Ren" <[email protected] <mailto:[email protected]>>
wrote:
Hi,
Your LVM version and kernel version please?
like:
""""
# lvm version
LVM version: 2.02.177(2) (2017-12-18)
Library version: 1.03.01 (2017-12-18)
Driver version: 4.35.0
# uname -a
Linux sle15-c1-n1 4.12.14-9.1-default #1 SMP Fri Jan 19 09:13:51
UTC 2018 (849a2fe) x86_64 x86_64 x86_64 GNU/Linux
"""
Eric
On 02/03/2018 05:43 PM, Liwei wrote:
Hi list,
I had a LV that I was converting from linear to mirrored (not
raid1) whose source device failed partway-through during the
initial
sync.
I've since recovered the source device, but it seems like the
mirror is still acting as if some blocks are not readable? I'm
getting
this in my logs, and the FS is full of errors:
[ +1.613126] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.000278] device-mapper: raid1: Primary mirror (253:25) failed
while out-of-sync: Reads may fail.
[ +0.085916] device-mapper: raid1: Mirror read failed.
[ +0.196562] device-mapper: raid1: Mirror read failed.
[ +0.000237] Buffer I/O error on dev dm-27, logical block
5371800560,
async page read
[ +0.592135] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.082882] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.246945] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.107374] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.083344] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.114949] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.085056] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.203929] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.157953] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +3.065247] recovery_complete: 23 callbacks suppressed
[ +0.000001] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.128064] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.103100] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.107827] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.140871] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.132844] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.124698] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.138502] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.117827] device-mapper: raid1: Unable to read primary mirror
during recovery
[ +0.125705] device-mapper: raid1: Unable to read primary mirror
during recovery
[Feb 3 17:09] device-mapper: raid1: Mirror read failed.
[ +0.167553] device-mapper: raid1: Mirror read failed.
[ +0.000268] Buffer I/O error on dev dm-27, logical block
5367765816,
async page read
[ +0.135138] device-mapper: raid1: Mirror read failed.
[ +0.000238] Buffer I/O error on dev dm-27, logical block
5367765816,
async page read
[ +0.000365] device-mapper: raid1: Mirror read failed.
[ +0.000315] device-mapper: raid1: Mirror read failed.
[ +0.000213] Buffer I/O error on dev dm-27, logical block
5367896888,
async page read
[ +0.000276] device-mapper: raid1: Mirror read failed.
[ +0.000199] Buffer I/O error on dev dm-27, logical block
5367765816,
async page read
However, if I take down the destination device and
restart the LV
with --activateoption partial, I can read my data and everything
checks out.
My theory (and what I observed) is that lvm continued the
initial
sync even after the source drive stopped responding, and has now
mapped the blocks that it 'synced' as dead. How can I make lvm
retry
those blocks again?
In fact, I don't trust the mirror anymore, is there a way
I can
conduct a scrub of the mirror after the initial sync is done?
I read
about --syncaction check, but seems like it only notes the
number of
inconsistencies. Can I have lvm re-mirror the inconsistencies
from the
source to destination device? I trust the source device
because we ran
a btrfs scrub on it and it reported that all checksums are valid.
It took months for the mirror sync to get to this stage
(actually,
why does it take months to mirror 20TB?), I don't want to
start it all
over again.
Warm regards,
Liwei
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