Re: Chunk root problem

[Austin S. Hemmelgarn]

On 2017-07-10 00:21, Daniel Brady wrote:

On 7/7/2017 1:06 AM, Daniel Brady wrote:

On 7/6/2017 11:48 PM, Roman Mamedov wrote:

On Wed, 5 Jul 2017 22:10:35 -0600
Daniel Brady  wrote:


parent transid verify failed


Typically in Btrfs terms this means "you're screwed", fsck will not fix it, and
nobody will know how to fix or what is the cause either. Time to restore from
backups! Or look into "btrfs restore" if you don't have any.

In your case it's especially puzzling as the difference in transid numbers is
really significant (about 100K), almost like the FS was operating for months
without updating some parts of itself -- and no checksum errors either, so
all looks correct, except that everything is horribly wrong.

This kind of error seems to occur more often in RAID setups, either Btrfs
native RAID, or with Btrfs on top of other RAID setups -- i.e. where it
becomes a complex issue that all writes to multi devices DO complete IN order,
in case of an unclean shutdown. (which is much simpler on a single device FS).

Also one of your disks or cables is failing (was /dev/sde on that boot, but may
get a different index next boot), check SMART data for it and replace.


[   21.230919] BTRFS info (device sdf): bdev /dev/sde errs: wr 402545, rd
234683174, flush 194501, corrupt 0, gen 0




Well that's not good news. Unfortunately I made a fatal error in not
having a backup. Restore looks like I could recover a good chunk of it
from the dry runs, however it has a lot of trouble reading many files.
I'm sure that is related to the one disk (sde). Drives were setup as raid56.

After updating the kernel as suggested in the email from Duncan it
reduced the "parent transid verify" errors down to just one and the errs
on sde still exist.

[   21.400190] BTRFS info (device sdb): use no compression
[   21.400191] BTRFS info (device sdb): disk space caching is enabled
[   21.400192] BTRFS info (device sdb): has skinny extents
[   21.584923] BTRFS info (device sdb): bdev /dev/sde errs: wr 402545,
rd 234683174, flush 194501, corrupt 0, gen 0
[   23.394788] BTRFS error (device sdb): parent transid verify failed on
5257838690304 wanted 591492 found 489231
[   23.416489] BTRFS error (device sdb): parent transid verify failed on
5257838690304 wanted 591492 found 489231
[   23.416524] BTRFS error (device sdb): failed to read block groups: -5
[   23.448478] BTRFS error (device sdb): open_ctree failed

I ran a SMART test as you suggested with a passing result. I also
swapped SATA cables & power with another drive and the error followed
the drive confirmed by the serial via SMART. It seems like it just can't
read from that one drive for whatever reason. I also tried disconnecting
the drive and trying to mount it degraded with no luck. Still had the
transid error just with null as the bdev.

smartctl -a /dev/sde
smartctl 6.2 2013-07-26 r3841 [x86_64-linux-4.12.0-1.el7.elrepo.x86_64]
(local build)
Copyright (C) 2002-13, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family: Western Digital Red (AF)
Device Model: WDC WD30EFRX-68EUZN0
Serial Number:WD-WCC4N0PEYTEV
LU WWN Device Id: 5 0014ee 2b7dbfe54
Firmware Version: 82.00A82
User Capacity:3,000,592,982,016 bytes [3.00 TB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Rotation Rate:5400 rpm
Device is:In smartctl database [for details use: -P show]
ATA Version is:   ACS-2 (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:Fri Jul  7 00:30:10 2017 MDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x00) Offline data collection activity
 was never started.
 Auto Offline Data Collection:
Disabled.
Self-test execution status:  (   0) The previous self-test routine
completed
 without error or no self-test
has ever
 been run.
Total time to complete Offline
data collection:(40500) seconds.
Offline data collection
capabilities:(0x7b) SMART execute Offline immediate.
 Auto Offline data collection
on/off support.
 Suspend Offline collection upon new
 command.
 Offline surface scan supported.
 Self-test supported.
 Conveyance Self-test supported.
 Selective Self-test supported.
SMART capabilities:(0x0003) Saves SMART data before entering
 

Re: Chunk root problem

[Daniel Brady]

On 7/7/2017 1:06 AM, Daniel Brady wrote:
> On 7/6/2017 11:48 PM, Roman Mamedov wrote:
>> On Wed, 5 Jul 2017 22:10:35 -0600
>> Daniel Brady  wrote:
>>
>>> parent transid verify failed
>>
>> Typically in Btrfs terms this means "you're screwed", fsck will not fix it, 
>> and
>> nobody will know how to fix or what is the cause either. Time to restore from
>> backups! Or look into "btrfs restore" if you don't have any.
>>
>> In your case it's especially puzzling as the difference in transid numbers is
>> really significant (about 100K), almost like the FS was operating for months
>> without updating some parts of itself -- and no checksum errors either, so
>> all looks correct, except that everything is horribly wrong.
>>
>> This kind of error seems to occur more often in RAID setups, either Btrfs
>> native RAID, or with Btrfs on top of other RAID setups -- i.e. where it
>> becomes a complex issue that all writes to multi devices DO complete IN 
>> order,
>> in case of an unclean shutdown. (which is much simpler on a single device 
>> FS).
>>
>> Also one of your disks or cables is failing (was /dev/sde on that boot, but 
>> may
>> get a different index next boot), check SMART data for it and replace.
>>
>>> [   21.230919] BTRFS info (device sdf): bdev /dev/sde errs: wr 402545, rd
>>> 234683174, flush 194501, corrupt 0, gen 0
>>
> 
> Well that's not good news. Unfortunately I made a fatal error in not
> having a backup. Restore looks like I could recover a good chunk of it
> from the dry runs, however it has a lot of trouble reading many files.
> I'm sure that is related to the one disk (sde). Drives were setup as raid56.
> 
> After updating the kernel as suggested in the email from Duncan it
> reduced the "parent transid verify" errors down to just one and the errs
> on sde still exist.
> 
> [   21.400190] BTRFS info (device sdb): use no compression
> [   21.400191] BTRFS info (device sdb): disk space caching is enabled
> [   21.400192] BTRFS info (device sdb): has skinny extents
> [   21.584923] BTRFS info (device sdb): bdev /dev/sde errs: wr 402545,
> rd 234683174, flush 194501, corrupt 0, gen 0
> [   23.394788] BTRFS error (device sdb): parent transid verify failed on
> 5257838690304 wanted 591492 found 489231
> [   23.416489] BTRFS error (device sdb): parent transid verify failed on
> 5257838690304 wanted 591492 found 489231
> [   23.416524] BTRFS error (device sdb): failed to read block groups: -5
> [   23.448478] BTRFS error (device sdb): open_ctree failed
> 
> I ran a SMART test as you suggested with a passing result. I also
> swapped SATA cables & power with another drive and the error followed
> the drive confirmed by the serial via SMART. It seems like it just can't
> read from that one drive for whatever reason. I also tried disconnecting
> the drive and trying to mount it degraded with no luck. Still had the
> transid error just with null as the bdev.
> 
> smartctl -a /dev/sde
> smartctl 6.2 2013-07-26 r3841 [x86_64-linux-4.12.0-1.el7.elrepo.x86_64]
> (local build)
> Copyright (C) 2002-13, Bruce Allen, Christian Franke, www.smartmontools.org
> 
> === START OF INFORMATION SECTION ===
> Model Family: Western Digital Red (AF)
> Device Model: WDC WD30EFRX-68EUZN0
> Serial Number:WD-WCC4N0PEYTEV
> LU WWN Device Id: 5 0014ee 2b7dbfe54
> Firmware Version: 82.00A82
> User Capacity:3,000,592,982,016 bytes [3.00 TB]
> Sector Sizes: 512 bytes logical, 4096 bytes physical
> Rotation Rate:5400 rpm
> Device is:In smartctl database [for details use: -P show]
> ATA Version is:   ACS-2 (minor revision not indicated)
> SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)
> Local Time is:Fri Jul  7 00:30:10 2017 MDT
> SMART support is: Available - device has SMART capability.
> SMART support is: Enabled
> 
> === START OF READ SMART DATA SECTION ===
> SMART overall-health self-assessment test result: PASSED
> 
> General SMART Values:
> Offline data collection status:  (0x00) Offline data collection activity
> was never started.
> Auto Offline Data Collection:
> Disabled.
> Self-test execution status:  (   0) The previous self-test routine
> completed
> without error or no self-test
> has ever
> been run.
> Total time to complete Offline
> data collection:(40500) seconds.
> Offline data collection
> capabilities:(0x7b) SMART execute Offline immediate.
> Auto Offline data collection
> on/off support.
> Suspend Offline collection upon new
> command.
> Offline surface scan supported.
> Self-test supported.
> Conveyance Self-test 

Re: Chunk root problem

[Daniel Brady]

On 7/6/2017 11:48 PM, Roman Mamedov wrote:
> On Wed, 5 Jul 2017 22:10:35 -0600
> Daniel Brady  wrote:
> 
>> parent transid verify failed
> 
> Typically in Btrfs terms this means "you're screwed", fsck will not fix it, 
> and
> nobody will know how to fix or what is the cause either. Time to restore from
> backups! Or look into "btrfs restore" if you don't have any.
> 
> In your case it's especially puzzling as the difference in transid numbers is
> really significant (about 100K), almost like the FS was operating for months
> without updating some parts of itself -- and no checksum errors either, so
> all looks correct, except that everything is horribly wrong.
> 
> This kind of error seems to occur more often in RAID setups, either Btrfs
> native RAID, or with Btrfs on top of other RAID setups -- i.e. where it
> becomes a complex issue that all writes to multi devices DO complete IN order,
> in case of an unclean shutdown. (which is much simpler on a single device FS).
> 
> Also one of your disks or cables is failing (was /dev/sde on that boot, but 
> may
> get a different index next boot), check SMART data for it and replace.
> 
>> [   21.230919] BTRFS info (device sdf): bdev /dev/sde errs: wr 402545, rd
>> 234683174, flush 194501, corrupt 0, gen 0
> 

Well that's not good news. Unfortunately I made a fatal error in not
having a backup. Restore looks like I could recover a good chunk of it
from the dry runs, however it has a lot of trouble reading many files.
I'm sure that is related to the one disk (sde). Drives were setup as raid56.

After updating the kernel as suggested in the email from Duncan it
reduced the "parent transid verify" errors down to just one and the errs
on sde still exist.

[   21.400190] BTRFS info (device sdb): use no compression
[   21.400191] BTRFS info (device sdb): disk space caching is enabled
[   21.400192] BTRFS info (device sdb): has skinny extents
[   21.584923] BTRFS info (device sdb): bdev /dev/sde errs: wr 402545,
rd 234683174, flush 194501, corrupt 0, gen 0
[   23.394788] BTRFS error (device sdb): parent transid verify failed on
5257838690304 wanted 591492 found 489231
[   23.416489] BTRFS error (device sdb): parent transid verify failed on
5257838690304 wanted 591492 found 489231
[   23.416524] BTRFS error (device sdb): failed to read block groups: -5
[   23.448478] BTRFS error (device sdb): open_ctree failed

I ran a SMART test as you suggested with a passing result. I also
swapped SATA cables & power with another drive and the error followed
the drive confirmed by the serial via SMART. It seems like it just can't
read from that one drive for whatever reason. I also tried disconnecting
the drive and trying to mount it degraded with no luck. Still had the
transid error just with null as the bdev.

smartctl -a /dev/sde
smartctl 6.2 2013-07-26 r3841 [x86_64-linux-4.12.0-1.el7.elrepo.x86_64]
(local build)
Copyright (C) 2002-13, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family: Western Digital Red (AF)
Device Model: WDC WD30EFRX-68EUZN0
Serial Number:WD-WCC4N0PEYTEV
LU WWN Device Id: 5 0014ee 2b7dbfe54
Firmware Version: 82.00A82
User Capacity:3,000,592,982,016 bytes [3.00 TB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Rotation Rate:5400 rpm
Device is:In smartctl database [for details use: -P show]
ATA Version is:   ACS-2 (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:Fri Jul  7 00:30:10 2017 MDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x00) Offline data collection activity
was never started.
Auto Offline Data Collection:
Disabled.
Self-test execution status:  (   0) The previous self-test routine
completed
without error or no self-test
has ever
been run.
Total time to complete Offline
data collection:(40500) seconds.
Offline data collection
capabilities:(0x7b) SMART execute Offline immediate.
Auto Offline data collection
on/off support.
Suspend Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
Conveyance Self-test supported.
Selective Self-test supported.
SMART capabilities:(0x0003) Saves SMART data before entering
power-saving mode.
 

Re: Chunk root problem

[Daniel Brady]

On 7/6/2017 2:26 AM, Duncan wrote:
> Daniel Brady posted on Wed, 05 Jul 2017 22:10:35 -0600 as excerpted:
>
>> My system suddenly decided it did not want to mount my BTRFS setup. I
>> recently rebooted the computer. When it came back, the file system was
>> in read only mode. I gave it another boot, but now it does not want to
>> mount at all. Anything I can do to recover? This is a Rockstor setup
>> that I have had running for about a year.
>>
>> uname -a
>> Linux hobonas 4.10.6-1.el7.elrepo.x86_64 #1 SMP Sun Mar 26
>> 12:19:32 EDT 2017 x86_64 x86_64 x86_64 GNU/Linux
>>
>> btrfs --version
>> btrfs-progs v4.10.1
>
> FWIW, open ctree failed is the btrfs-generic error, but the transid
> faileds may provide some help.
>
> Addressing the easy answer first...
>
> What btrfs raid mode was it configured for?  If raid56, you want the
> brand new 4.12 kernel at least, as there were serious bugs in previous
> kernels' raid56 mode.  DO NOT ATTEMPT A FIX OF RAID56 MODE WITH AN
> EARLIER KERNEL, IT'S VERY LIKELY TO ONLY CAUSE FURTHER DAMAGE!  But if
> you're lucky, kernel 4.12 can auto-repair it.
>
> With those fixes the known bugs are fixed, but we'll need to wait a
> few
> cycles to see what the reports are.  Even then, however, due to the
> infamous parity-raid write hole and the fact that the parity isn't
> checksummed, it's not going to be as stable as raid1 or raid10 mode.
> Parity-checksumming will take a new implementation and I'm not sure if
> anyone's actually working on that or not.  But at least until we see
> how
> stable the newer raid56 code is, 2-4 kernel cycles, it's not
> recommended
> except for testing only, with even more backups than normal.
>
> If you were raid1 or raid10 mode, the raid mode is stable so it's a
> different issue.  I'll let the experts take it from here.  Single or
> raid0 mode would of course be similar, but without the protection of
> the
> second copy, making it less resilient.

The raid mode was configured for raid56... unfortunately. I learned of
the potential instability after it died. I have not attempted to repair
it yet because of the possible corruption. I've only tried various ways
of mounting it and dry runs of the restore function.

I did as you mentioned and upgraded to kernel 4.12. The auto-repair
seemed to fix quite a few things, but it is not quite there. Even with a
few reboots.

uname -r
4.12.0-1.el7.elrepo.x86_64

rpm -qa | grep btrfs
btrfs-progs-4.10.1-0.rockstor.x86_64

dmesg
[   21.400190] BTRFS info (device sdb): use no compression
[   21.400191] BTRFS info (device sdb): disk space caching is enabled
[   21.400192] BTRFS info (device sdb): has skinny extents
[   21.584923] BTRFS info (device sdb): bdev /dev/sde errs: wr 402545,
rd 234683174, flush 194501, corrupt 0, gen 0
[   23.394788] BTRFS error (device sdb): parent transid verify failed on
5257838690304 wanted 591492 found 489231
[   23.416489] BTRFS error (device sdb): parent transid verify failed on
5257838690304 wanted 591492 found 489231
[   23.416524] BTRFS error (device sdb): failed to read block groups: -5
[   23.448478] BTRFS error (device sdb): open_ctree failed

-Dan
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Re: Chunk root problem

[Roman Mamedov]

On Wed, 5 Jul 2017 22:10:35 -0600
Daniel Brady  wrote:

> parent transid verify failed

Typically in Btrfs terms this means "you're screwed", fsck will not fix it, and
nobody will know how to fix or what is the cause either. Time to restore from
backups! Or look into "btrfs restore" if you don't have any.

In your case it's especially puzzling as the difference in transid numbers is
really significant (about 100K), almost like the FS was operating for months
without updating some parts of itself -- and no checksum errors either, so
all looks correct, except that everything is horribly wrong.

This kind of error seems to occur more often in RAID setups, either Btrfs
native RAID, or with Btrfs on top of other RAID setups -- i.e. where it
becomes a complex issue that all writes to multi devices DO complete IN order,
in case of an unclean shutdown. (which is much simpler on a single device FS).

Also one of your disks or cables is failing (was /dev/sde on that boot, but may
get a different index next boot), check SMART data for it and replace.

> [   21.230919] BTRFS info (device sdf): bdev /dev/sde errs: wr 402545, rd
> 234683174, flush 194501, corrupt 0, gen 0

-- 
With respect,
Roman
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Re: Chunk root problem

[Duncan]

Daniel Brady posted on Wed, 05 Jul 2017 22:10:35 -0600 as excerpted:

> My system suddenly decided it did not want to mount my BTRFS setup. I
> recently rebooted the computer. When it came back, the file system was
> in read only mode. I gave it another boot, but now it does not want to
> mount at all. Anything I can do to recover? This is a Rockstor setup
> that I have had running for about a year.
> 
> uname -a
> Linux hobonas 4.10.6-1.el7.elrepo.x86_64 #1 SMP Sun Mar 26
> 12:19:32 EDT 2017 x86_64 x86_64 x86_64 GNU/Linux
> 
> btrfs --version
> btrfs-progs v4.10.1

FWIW, open ctree failed is the btrfs-generic error, but the transid 
faileds may provide some help.

Addressing the easy answer first...

What btrfs raid mode was it configured for?  If raid56, you want the 
brand new 4.12 kernel at least, as there were serious bugs in previous 
kernels' raid56 mode.  DO NOT ATTEMPT A FIX OF RAID56 MODE WITH AN 
EARLIER KERNEL, IT'S VERY LIKELY TO ONLY CAUSE FURTHER DAMAGE!  But if 
you're lucky, kernel 4.12 can auto-repair it.

With those fixes the known bugs are fixed, but we'll need to wait a few 
cycles to see what the reports are.  Even then, however, due to the 
infamous parity-raid write hole and the fact that the parity isn't 
checksummed, it's not going to be as stable as raid1 or raid10 mode.  
Parity-checksumming will take a new implementation and I'm not sure if 
anyone's actually working on that or not.  But at least until we see how 
stable the newer raid56 code is, 2-4 kernel cycles, it's not recommended 
except for testing only, with even more backups than normal.

If you were raid1 or raid10 mode, the raid mode is stable so it's a 
different issue.  I'll let the experts take it from here.  Single or 
raid0 mode would of course be similar, but without the protection of the 
second copy, making it less resilient.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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Chunk root problem

[Daniel Brady]

Hello,

My system suddenly decided it did not want to mount my BTRFS setup. I
recently rebooted the computer. When it came back, the file system was
in read only mode. I gave it another boot, but now it does not want to
mount at all. Anything I can do to recover? This is a Rockstor setup
that I have had running for about a year.

uname -a
Linux hobonas 4.10.6-1.el7.elrepo.x86_64 #1 SMP Sun Mar 26 12:19:32
EDT 2017 x86_64 x86_64 x86_64 GNU/Linux

btrfs --version
btrfs-progs v4.10.1

btrfs fi show
Label: 'rockstor_rockstor'  uuid: 33e2af57-c30a-468a-9ed5-22994780f6b4
Total devices 1 FS bytes used 5.50GiB
devid1 size 215.39GiB used 80.02GiB path /dev/sda3

Label: 'Nexus'  uuid: 1c3595a9-3faa-4973-affc-ee8d14d922bf
Total devices 5 FS bytes used 3.93TiB
devid1 size 2.73TiB used 1.12TiB path /dev/sdd
devid2 size 2.73TiB used 1.12TiB path /dev/sdb
devid3 size 2.73TiB used 1.12TiB path /dev/sdc
devid4 size 2.73TiB used 1.12TiB path /dev/sdf
devid5 size 2.73TiB used 1.12TiB path /dev/sde

dmesg
[   18.572846] BTRFS: device label Nexus devid 2 transid 595679 /dev/sdb
[   18.572933] BTRFS: device label Nexus devid 3 transid 595679 /dev/sdc
[   18.573027] BTRFS: device label Nexus devid 1 transid 595679 /dev/sdd
[   18.573119] BTRFS: device label Nexus devid 5 transid 595679 /dev/sde
[   18.573200] BTRFS: device label Nexus devid 4 transid 595679 /dev/sdf
[   20.846060] device-mapper: uevent: version 1.0.3
[   20.846114] device-mapper: ioctl: 4.35.0-ioctl (2016-06-23)
initialised: dm-de...@redhat.com
[   21.073884] BTRFS info (device sdf): use no compression
[   21.073886] BTRFS info (device sdf): disk space caching is enabled
[   21.073887] BTRFS info (device sdf): has skinny extents
[   21.084353] BTRFS error (device sdf): parent transid verify failed
on 8419247390720 wanted 542466 found 485869
[   21.230919] BTRFS info (device sdf): bdev /dev/sde errs: wr 402545,
rd 234683174, flush 194501, corrupt 0, gen 0
[   21.794749] BTRFS error (device sdf): parent transid verify failed
on 893915128 wanted 594920 found 490791
[   21.841317] BTRFS error (device sdf): parent transid verify failed
on 8939187814400 wanted 594923 found 490824
[   21.870392] BTRFS error (device sdf): parent transid verify failed
on 8418984427520 wanted 594877 found 490575
[   21.951901] BTRFS error (device sdf): parent transid verify failed
on 8939107860480 wanted 594915 found 465207
[   22.015789] BTRFS error (device sdf): parent transid verify failed
on 8939284430848 wanted 594958 found 465274
[   22.034840] BTRFS error (device sdf): parent transid verify failed
on 8418907701248 wanted 594869 found 351596
[   22.070516] BTRFS error (device sdf): parent transid verify failed
on 8939032035328 wanted 594899 found 465175
[   22.091734] BTRFS error (device sdf): parent transid verify failed
on 8939123818496 wanted 594917 found 490777
[   22.110531] BTRFS error (device sdf): parent transid verify failed
on 8939121917952 wanted 594917 found 490775
[   23.393973] BTRFS error (device sdf): failed to read block groups: -5
[   23.419807] BTRFS error (device sdf): open_ctree failed

mount -t btrfs -o recovery,ro /dev/sdb /mnt2/Nexus
mount: wrong fs type, bad option, bad superblock on /dev/sdb,
   missing codepage or helper program, or other error

   In some cases useful info is found in syslog - try
   dmesg | tail or so.

Thanks,
Dan
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