Re: raid1 has failing disks, but smart is clear

[Corey Coughlin]

Hi Andrei,
Thanks for the info, sorry about the improper terminology.  In 
better news, I discovered that one disk wasn't getting recognized by the 
OS at certain outputs of one of my mini-sas to sata cables, so I got a 
new one, and the disk works fine on that.  So I'm that's at least one 
bad cable, I still have to check the other 3, though.


-- Corey

On 07/08/2016 10:40 PM, Andrei Borzenkov wrote:

07.07.2016 09:40, Corey Coughlin пишет:

Hi Tomasz,
 Thanks for the response!  I should clear some things up, though.

On 07/06/2016 03:59 PM, Tomasz Kusmierz wrote:

On 6 Jul 2016, at 23:14, Corey Coughlin
 wrote:

Hi all,
 Hoping you all can help, have a strange problem, think I know
what's going on, but could use some verification.  I set up a raid1
type btrfs filesystem on an Ubuntu 16.04 system, here's what it looks
like:

btrfs fi show
Label: none  uuid: 597ee185-36ac-4b68-8961-d4adc13f95d4
 Total devices 10 FS bytes used 3.42TiB
 devid1 size 1.82TiB used 1.18TiB path /dev/sdd
 devid2 size 698.64GiB used 47.00GiB path /dev/sdk
 devid3 size 931.51GiB used 280.03GiB path /dev/sdm
 devid4 size 931.51GiB used 280.00GiB path /dev/sdl
 devid5 size 1.82TiB used 1.17TiB path /dev/sdi
 devid6 size 1.82TiB used 823.03GiB path /dev/sdj
 devid7 size 698.64GiB used 47.00GiB path /dev/sdg
 devid8 size 1.82TiB used 1.18TiB path /dev/sda
 devid9 size 1.82TiB used 1.18TiB path /dev/sdb
 devid   10 size 1.36TiB used 745.03GiB path /dev/sdh

Now when I say that the drives mount points change, I'm not saying they
change when I reboot.  They change while the system is running.  For
instance, here's the fi show after I ran a "check --repair" run this
afternoon:

btrfs fi show
Label: none  uuid: 597ee185-36ac-4b68-8961-d4adc13f95d4
 Total devices 10 FS bytes used 3.42TiB
 devid1 size 1.82TiB used 1.18TiB path /dev/sdd
 devid2 size 698.64GiB used 47.00GiB path /dev/sdk
 devid3 size 931.51GiB used 280.03GiB path /dev/sdm
 devid4 size 931.51GiB used 280.00GiB path /dev/sdl
 devid5 size 1.82TiB used 1.17TiB path /dev/sdi
 devid6 size 1.82TiB used 823.03GiB path /dev/sds
 devid7 size 698.64GiB used 47.00GiB path /dev/sdg
 devid8 size 1.82TiB used 1.18TiB path /dev/sda
 devid9 size 1.82TiB used 1.18TiB path /dev/sdb
 devid   10 size 1.36TiB used 745.03GiB path /dev/sdh

Notice that /dev/sdj in the previous run changed to /dev/sds.  There was
no reboot, the mount just changed.  I don't know why that is happening,
but it seems like the majority of the errors are on that drive.  But
given that I've fixed the start/stop issue on that disk, it probably
isn't a WD Green issue.

It's not "mount point", it is just device names. Do not make it sound
more confusing than it already is :)

This implies that disks drop off and reappear. Do you have "dmesg" or
log (/var/log/syslog or /var/log/messages or journalctl) for the same
period of time?



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Re: raid1 has failing disks, but smart is clear

[Andrei Borzenkov]

08.07.2016 04:24, Duncan пишет:
> Corey Coughlin posted on Wed, 06 Jul 2016 23:40:30 -0700 as excerpted:
> 
>> Well yeah, if I was mounting all the disks to different mount points, I
>> would definitely use UUIDs to get them mounted.  But I haven't seen any
>> way to set up a "mkfs.btrfs" command to use UUID or anything else for
>> individual drives.  Am I missing something?  I've been doing a lot of
>> googling.
> 
> FWIW, you can use the /dev/disk/by-*/* symlinks (as normally setup by 
> udev) to reference various devices.
> 

Current udev ships rule that calls equivalent of "btrfs device ready
$dev", where $dev is the canonical kernel device name. btrfs kernel
driver will update internal list of device names when it gets this
ioctl, which means that unless you explicitly pass full list of
/dev/disk/by-*/* during mount you will see those kernel names.

And even then as soon as device for some reason dis- and re-appears (as
is apparently the case here) it will be renamed back by udev when "add"
event is seen.
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Re: raid1 has failing disks, but smart is clear

[Andrei Borzenkov]

07.07.2016 09:40, Corey Coughlin пишет:
> Hi Tomasz,
> Thanks for the response!  I should clear some things up, though.
> 
> On 07/06/2016 03:59 PM, Tomasz Kusmierz wrote:
>>> On 6 Jul 2016, at 23:14, Corey Coughlin
>>>  wrote:
>>>
>>> Hi all,
>>> Hoping you all can help, have a strange problem, think I know
>>> what's going on, but could use some verification.  I set up a raid1
>>> type btrfs filesystem on an Ubuntu 16.04 system, here's what it looks
>>> like:
>>>
>>> btrfs fi show
>>> Label: none  uuid: 597ee185-36ac-4b68-8961-d4adc13f95d4
>>> Total devices 10 FS bytes used 3.42TiB
>>> devid1 size 1.82TiB used 1.18TiB path /dev/sdd
>>> devid2 size 698.64GiB used 47.00GiB path /dev/sdk
>>> devid3 size 931.51GiB used 280.03GiB path /dev/sdm
>>> devid4 size 931.51GiB used 280.00GiB path /dev/sdl
>>> devid5 size 1.82TiB used 1.17TiB path /dev/sdi
>>> devid6 size 1.82TiB used 823.03GiB path /dev/sdj
>>> devid7 size 698.64GiB used 47.00GiB path /dev/sdg
>>> devid8 size 1.82TiB used 1.18TiB path /dev/sda
>>> devid9 size 1.82TiB used 1.18TiB path /dev/sdb
>>> devid   10 size 1.36TiB used 745.03GiB path /dev/sdh
> Now when I say that the drives mount points change, I'm not saying they
> change when I reboot.  They change while the system is running.  For
> instance, here's the fi show after I ran a "check --repair" run this
> afternoon:
> 
> btrfs fi show
> Label: none  uuid: 597ee185-36ac-4b68-8961-d4adc13f95d4
> Total devices 10 FS bytes used 3.42TiB
> devid1 size 1.82TiB used 1.18TiB path /dev/sdd
> devid2 size 698.64GiB used 47.00GiB path /dev/sdk
> devid3 size 931.51GiB used 280.03GiB path /dev/sdm
> devid4 size 931.51GiB used 280.00GiB path /dev/sdl
> devid5 size 1.82TiB used 1.17TiB path /dev/sdi
> devid6 size 1.82TiB used 823.03GiB path /dev/sds
> devid7 size 698.64GiB used 47.00GiB path /dev/sdg
> devid8 size 1.82TiB used 1.18TiB path /dev/sda
> devid9 size 1.82TiB used 1.18TiB path /dev/sdb
> devid   10 size 1.36TiB used 745.03GiB path /dev/sdh
> 
> Notice that /dev/sdj in the previous run changed to /dev/sds.  There was
> no reboot, the mount just changed.  I don't know why that is happening,
> but it seems like the majority of the errors are on that drive.  But
> given that I've fixed the start/stop issue on that disk, it probably
> isn't a WD Green issue.

It's not "mount point", it is just device names. Do not make it sound
more confusing than it already is :)

This implies that disks drop off and reappear. Do you have "dmesg" or
log (/var/log/syslog or /var/log/messages or journalctl) for the same
period of time?

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Re: raid1 has failing disks, but smart is clear

[Corey Coughlin]

Hi all,
One thing I may not have made clear, this wasn't a system that has 
been running for a month and just became up corrupt out of nowhere, the 
corruption showed up the first time I tried to run a filesystem balance, 
basically the day after I set up the filesystem and copied files over.  
I was hoping to get it stable and then add some more disks, but since it 
wasn't stable right off the top, I'm assuming the problem is bigger than 
some bad memory. I ran the stress.sh on two disks connected to ports on 
the motherboard, that seemed to work fine.  And I'm using a pair of WD 
green drives, in case there's an issue with those.  I did order some WD 
red NAS drives, hoping they arrive soon.  I'm running the stress now 
with them connected to the SAS card, trying to only let them run for a 
day to see if something bad happens, it's a 4 port card so if there's a 
problem with a specific port or cable, it could take me a while to find 
it.  I'm hoping it shows up in a somewhat obvious way.  But thanks for 
all the help, the stress.sh runs give me a clear way to try to debug 
this, thanks again for that tip.


--- Corey

On 07/08/2016 05:14 AM, Austin S. Hemmelgarn wrote:

On 2016-07-08 07:14, Tomasz Kusmierz wrote:


Well, I was able to run memtest on the system last night, that 
passed with
flying colors, so I'm now leaning toward the problem being in the 
sas card.

But I'll have to run some more tests.



Seriously use the "stres.sh" for couple of days, When I was running
memtest it was running continuously for 3 days without the error, day
of stres.sh and errors started showing up.
Be VERY careful with trusting any sort of that tool, modern CPU's lye
to you continuously !!!
1. You may think that you've wrote best on the planet code that
bypasses a CPU cache, but in reality since CPU's are multicore you can
end up with overzealous MPMD traping you inside of you cache memory
and all you resting will do is write a page (trapped in cache) read it
from cache (coherency mechanism, not the mis/hit one) will trap you
inside of L3 so you have no clue you don't touch the ram, then CPU
will just dump your page to RAM and "job done"
2. Since coherency problems and real problems with non blocking on
mpmd you can have a DMA controller sucking pages out your own cache,
due to ram being marked as dirty and CPU will try to spare the time
and accelerate the operation to push DMA straigh out of L3 to
somewhere else (mentioning that sine some testers use crazy way of
forcing your ram access via DMA to somewhere and back to force droping
out of L3)
3. This one is actually funny: some testers didn't claim the pages to
the process so for some reason pages that the were using were not
showing up as used / dirty etc so all the testing was done 32kB of L1
... tests were fast thou :)

srters.sh will test operation of the whole system !!! it shifts a lot
of data so disks are engaged, CPU keeps pumping out CRC32 all the time
so it's busy, RAM gets hit nicely as well due to high DMA.

Agreed, never just trust memtest86 or memtest86+.

FWIW< here's the routine I go through to test new RAM:
1. Run regular memtest86 for at least 3 full cycles in full SMP mode 
(F2 while starting up to force SMP).  On some systems this may hang, 
but that's an issue in the BIOS's setup of the CPU and MC, not the 
RAM, and is generally not indicative of a system which will have issues.
2. Run regular memtest86 for at least 3 full cycles in regular UP mode 
(the default on most non-NUMA hardware).
3. Repeat 1 and 2 with memtest86+.  It's diverged enough from regular 
memtest86 that it's functionally a separate tool, and I've seen RAM 
that passes one but not the other on multiple occasions before.
4. Boot SystemRescueCD, download a copy of the Linux sources, and run 
as many allmodconfig builds in parallel as I have CPU's, each with a 
number of make jobs equal to the twice number of CPU's (so each CPU 
ends up running at least two threads).  This forces enough context 
switching to completely trash even the L3 cache on almost any modern 
processor, which means it forces things out to RAM.  It won't hit all 
your RAM, but I've found it to be a relatively reliable way to verify 
the memory bus and the memory controller work properly.
5. Still from SystemRescueCD, use a tool called memtester (essentially 
memtest86, but run from userspace) to check the RAM.
6. Still from SystemRescueCD, use sha1sum to compute SHA-1 hashes of 
all the disks in the system, using at least 8 instances of sha1sum per 
CPU core, and make sure that all the sums for a disk match.
7. Do 6 again, but using cat to compute the sum of a concatenation of 
all the disks in the system (so the individual commands end up being 
`cat /dev/sd? | sha1sum`).  This will rapidly use all available memory 
on the system and keep it in use for quite a while.
8. If I'm using my home server system, I also have a special virtual 
runlevel set up where I spin up 4 times as many VM's as I 

Re: raid1 has failing disks, but smart is clear

[Austin S. Hemmelgarn]

On 2016-07-08 07:14, Tomasz Kusmierz wrote:


Well, I was able to run memtest on the system last night, that passed with
flying colors, so I'm now leaning toward the problem being in the sas card.
But I'll have to run some more tests.



Seriously use the "stres.sh" for couple of days, When I was running
memtest it was running continuously for 3 days without the error, day
of stres.sh and errors started showing up.
Be VERY careful with trusting any sort of that tool, modern CPU's lye
to you continuously !!!
1. You may think that you've wrote best on the planet code that
bypasses a CPU cache, but in reality since CPU's are multicore you can
end up with overzealous MPMD traping you inside of you cache memory
and all you resting will do is write a page (trapped in cache) read it
from cache (coherency mechanism, not the mis/hit one) will trap you
inside of L3 so you have no clue you don't touch the ram, then CPU
will just dump your page to RAM and "job done"
2. Since coherency problems and real problems with non blocking on
mpmd you can have a DMA controller sucking pages out your own cache,
due to ram being marked as dirty and CPU will try to spare the time
and accelerate the operation to push DMA straigh out of L3 to
somewhere else (mentioning that sine some testers use crazy way of
forcing your ram access via DMA to somewhere and back to force droping
out of L3)
3. This one is actually funny: some testers didn't claim the pages to
the process so for some reason pages that the were using were not
showing up as used / dirty etc so all the testing was done 32kB of L1
... tests were fast thou :)

srters.sh will test operation of the whole system !!! it shifts a lot
of data so disks are engaged, CPU keeps pumping out CRC32 all the time
so it's busy, RAM gets hit nicely as well due to high DMA.

Agreed, never just trust memtest86 or memtest86+.

FWIW< here's the routine I go through to test new RAM:
1. Run regular memtest86 for at least 3 full cycles in full SMP mode (F2 
while starting up to force SMP).  On some systems this may hang, but 
that's an issue in the BIOS's setup of the CPU and MC, not the RAM, and 
is generally not indicative of a system which will have issues.
2. Run regular memtest86 for at least 3 full cycles in regular UP mode 
(the default on most non-NUMA hardware).
3. Repeat 1 and 2 with memtest86+.  It's diverged enough from regular 
memtest86 that it's functionally a separate tool, and I've seen RAM that 
passes one but not the other on multiple occasions before.
4. Boot SystemRescueCD, download a copy of the Linux sources, and run as 
many allmodconfig builds in parallel as I have CPU's, each with a number 
of make jobs equal to the twice number of CPU's (so each CPU ends up 
running at least two threads).  This forces enough context switching to 
completely trash even the L3 cache on almost any modern processor, which 
means it forces things out to RAM.  It won't hit all your RAM, but I've 
found it to be a relatively reliable way to verify the memory bus and 
the memory controller work properly.
5. Still from SystemRescueCD, use a tool called memtester (essentially 
memtest86, but run from userspace) to check the RAM.
6. Still from SystemRescueCD, use sha1sum to compute SHA-1 hashes of all 
the disks in the system, using at least 8 instances of sha1sum per CPU 
core, and make sure that all the sums for a disk match.
7. Do 6 again, but using cat to compute the sum of a concatenation of 
all the disks in the system (so the individual commands end up being 
`cat /dev/sd? | sha1sum`).  This will rapidly use all available memory 
on the system and keep it in use for quite a while.
8. If I'm using my home server system, I also have a special virtual 
runlevel set up where I spin up 4 times as many VM's as I have CPU cores 
(so on my current 8 core system, I spin up 32), all assigned a part of 
the RAM not used by the host (which I shrink to the minimum useable size 
of about 500MB), all running steps 1-3 in parallel.


It may also be worth mentioning that I've seen very poorly behaved HBA's 
that produce symptoms that look like bad RAM, including issues not 
related to the disks themselves, yet show no issues when regular memory 
testing is run.


When come to think about it, if your device points change during
operation of the system it might be an LSI card dying -> reinitialize
-> rediscovering drives -> drives show up in different point. On my
system I can hot swap sata and it will come up with different dev even
thou it was connected to same place on the controller.
Barring a few odd controllers I've seen which support hot-plug but not 
hot-remove, that shouldn't happen unless the device is in use, and in 
that case it only happens because of the existing open references to the 
device being held by whatever is using it.


I think, most important - I presume you run nonECC ?
And if not, how well shielded is your system?  You can often get by with 
non-ECC RAM if you have good EMI 

Re: raid1 has failing disks, but smart is clear

[Tomasz Kusmierz]

>
> Well, I was able to run memtest on the system last night, that passed with
> flying colors, so I'm now leaning toward the problem being in the sas card.
> But I'll have to run some more tests.
>

Seriously use the "stres.sh" for couple of days, When I was running
memtest it was running continuously for 3 days without the error, day
of stres.sh and errors started showing up.
Be VERY careful with trusting any sort of that tool, modern CPU's lye
to you continuously !!!
1. You may think that you've wrote best on the planet code that
bypasses a CPU cache, but in reality since CPU's are multicore you can
end up with overzealous MPMD traping you inside of you cache memory
and all you resting will do is write a page (trapped in cache) read it
from cache (coherency mechanism, not the mis/hit one) will trap you
inside of L3 so you have no clue you don't touch the ram, then CPU
will just dump your page to RAM and "job done"
2. Since coherency problems and real problems with non blocking on
mpmd you can have a DMA controller sucking pages out your own cache,
due to ram being marked as dirty and CPU will try to spare the time
and accelerate the operation to push DMA straigh out of L3 to
somewhere else (mentioning that sine some testers use crazy way of
forcing your ram access via DMA to somewhere and back to force droping
out of L3)
3. This one is actually funny: some testers didn't claim the pages to
the process so for some reason pages that the were using were not
showing up as used / dirty etc so all the testing was done 32kB of L1
... tests were fast thou :)

srters.sh will test operation of the whole system !!! it shifts a lot
of data so disks are engaged, CPU keeps pumping out CRC32 all the time
so it's busy, RAM gets hit nicely as well due to high DMA.

When come to think about it, if your device points change during
operation of the system it might be an LSI card dying -> reinitialize
-> rediscovering drives -> drives show up in different point. On my
system I can hot swap sata and it will come up with different dev even
thou it was connected to same place on the controller.

I think, most important - I presume you run nonECC ?
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Re: raid1 has failing disks, but smart is clear

[Corey Coughlin]

Hi Duncan,
Thanks for the info!  I've seen that done in the fstab, but it 
didn't work for me the last time I tried it on the command line. Worth a 
shot!


-- Corey

On 07/07/2016 06:24 PM, Duncan wrote:

Corey Coughlin posted on Wed, 06 Jul 2016 23:40:30 -0700 as excerpted:


Well yeah, if I was mounting all the disks to different mount points, I
would definitely use UUIDs to get them mounted.  But I haven't seen any
way to set up a "mkfs.btrfs" command to use UUID or anything else for
individual drives.  Am I missing something?  I've been doing a lot of
googling.

FWIW, you can use the /dev/disk/by-*/* symlinks (as normally setup by
udev) to reference various devices.

Of course because the identifiers behind by-uuid and by-label are per-
filesystem, those will normally only identify the one device of a multi-
device filesystem, but the by-id links ID on device serials and partition
number, and if you are using GPT partitioning, you have by-partuuid and
(if you set them when setting up the partitions) by-partlabel as well.



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Re: raid1 has failing disks, but smart is clear

[Corey Coughlin]

Hi Austin,
Thanks for the reply!  I'll go inline for more:

On 07/07/2016 04:58 AM, Austin S. Hemmelgarn wrote:

On 2016-07-06 18:59, Tomasz Kusmierz wrote:


On 6 Jul 2016, at 23:14, Corey Coughlin 
 wrote:


Hi all,
   Hoping you all can help, have a strange problem, think I know 
what's going on, but could use some verification.  I set up a raid1 
type btrfs filesystem on an Ubuntu 16.04 system, here's what it 
looks like:


btrfs fi show
Label: none  uuid: 597ee185-36ac-4b68-8961-d4adc13f95d4
   Total devices 10 FS bytes used 3.42TiB
   devid1 size 1.82TiB used 1.18TiB path /dev/sdd
   devid2 size 698.64GiB used 47.00GiB path /dev/sdk
   devid3 size 931.51GiB used 280.03GiB path /dev/sdm
   devid4 size 931.51GiB used 280.00GiB path /dev/sdl
   devid5 size 1.82TiB used 1.17TiB path /dev/sdi
   devid6 size 1.82TiB used 823.03GiB path /dev/sdj
   devid7 size 698.64GiB used 47.00GiB path /dev/sdg
   devid8 size 1.82TiB used 1.18TiB path /dev/sda
   devid9 size 1.82TiB used 1.18TiB path /dev/sdb
   devid   10 size 1.36TiB used 745.03GiB path /dev/sdh

I added a couple disks, and then ran a balance operation, and that 
took about 3 days to finish.  When it did finish, tried a scrub and 
got this message:


scrub status for 597ee185-36ac-4b68-8961-d4adc13f95d4
   scrub started at Sun Jun 26 18:19:28 2016 and was aborted after 
01:16:35

   total bytes scrubbed: 926.45GiB with 18849935 errors
   error details: read=18849935
   corrected errors: 5860, uncorrectable errors: 18844075, 
unverified errors: 0


So that seems bad.  Took a look at the devices and a few of them 
have errors:

...
[/dev/sdi].generation_errs 0
[/dev/sdj].write_io_errs   289436740
[/dev/sdj].read_io_errs289492820
[/dev/sdj].flush_io_errs   12411
[/dev/sdj].corruption_errs 0
[/dev/sdj].generation_errs 0
[/dev/sdg].write_io_errs   0
...
[/dev/sda].generation_errs 0
[/dev/sdb].write_io_errs   3490143
[/dev/sdb].read_io_errs111
[/dev/sdb].flush_io_errs   268
[/dev/sdb].corruption_errs 0
[/dev/sdb].generation_errs 0
[/dev/sdh].write_io_errs   5839
[/dev/sdh].read_io_errs2188
[/dev/sdh].flush_io_errs   11
[/dev/sdh].corruption_errs 1
[/dev/sdh].generation_errs 16373

So I checked the smart data for those disks, they seem perfect, no 
reallocated sectors, no problems.  But one thing I did notice is 
that they are all WD Green drives.  So I'm guessing that if they 
power down and get reassigned to a new /dev/sd* letter, that could 
lead to data corruption.  I used idle3ctl to turn off the shut down 
mode on all the green drives in the system, but I'm having trouble 
getting the filesystem working without the errors.  I tried a 'check 
--repair' command on it, and it seems to find a lot of verification 
errors, but it doesn't look like things are getting fixed.
 But I have all the data on it backed up on another system, so I can 
recreate this if I need to.  But here's what I want to know:


1.  Am I correct about the issues with the WD Green drives, if they 
change mounts during disk operations, will that corrupt data?
I just wanted to chip in with WD Green drives. I have a RAID10 
running on 6x2TB of those, actually had for ~3 years. If disk goes 
down for spin down, and you try to access something - kernel & FS & 
whole system will wait for drive to re-spin and everything works OK. 
I’ve never had a drive being reassigned to different /dev/sdX due to 
spin down / up.
2 years ago I was having a corruption due to not using ECC ram on my 
system and one of RAM modules started producing errors that were 
never caught up by CPU / MoBo. Long story short, guy here managed to 
point me to the right direction and I started shifting my data to 
hopefully new and not corrupted FS … but I was sceptical of similar 
issue that you have described AND I did raid1 and while mounted I did 
shift disk from one SATA port to another and FS managed to pick up 
the disk in new location and did not even blinked (as far as I 
remember there was syslog entry to say that disk vanished and then 
that disk was added)


Last word, you got plenty of errors in your SMART for transfer 
related stuff, please be advised that this may mean:

- faulty cable
- faulty mono controller
- faulty drive controller
- bad RAM - yes, mother board CAN use your ram for storing data and 
transfer related stuff … specially chapter ones.
It's worth pointing out that the most likely point here for data 
corruption assuming the cable and controllers are OK is during the DMA 
transfer from system RAM to the drive controller.  Even when dealing 
with really good HBA's that have an on-board NVRAM cache, you still 
have to copy the data out of system RAM at some point, and that's 
usually when the corruption occurs if the problem is with the RAM, CPU 
or MB.


Well, I was able to run memtest on the system last night, that passed 
with flying colors, so I'm now leaning toward the problem being in the 
sas card.  But 

Re: raid1 has failing disks, but smart is clear

[Duncan]

Corey Coughlin posted on Wed, 06 Jul 2016 23:40:30 -0700 as excerpted:

> Well yeah, if I was mounting all the disks to different mount points, I
> would definitely use UUIDs to get them mounted.  But I haven't seen any
> way to set up a "mkfs.btrfs" command to use UUID or anything else for
> individual drives.  Am I missing something?  I've been doing a lot of
> googling.

FWIW, you can use the /dev/disk/by-*/* symlinks (as normally setup by 
udev) to reference various devices.

Of course because the identifiers behind by-uuid and by-label are per-
filesystem, those will normally only identify the one device of a multi-
device filesystem, but the by-id links ID on device serials and partition 
number, and if you are using GPT partitioning, you have by-partuuid and 
(if you set them when setting up the partitions) by-partlabel as well.

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Re: raid1 has failing disks, but smart is clear

[Austin S. Hemmelgarn]

On 2016-07-06 18:59, Tomasz Kusmierz wrote:



On 6 Jul 2016, at 23:14, Corey Coughlin  wrote:

Hi all,
   Hoping you all can help, have a strange problem, think I know what's going 
on, but could use some verification.  I set up a raid1 type btrfs filesystem on 
an Ubuntu 16.04 system, here's what it looks like:

btrfs fi show
Label: none  uuid: 597ee185-36ac-4b68-8961-d4adc13f95d4
   Total devices 10 FS bytes used 3.42TiB
   devid1 size 1.82TiB used 1.18TiB path /dev/sdd
   devid2 size 698.64GiB used 47.00GiB path /dev/sdk
   devid3 size 931.51GiB used 280.03GiB path /dev/sdm
   devid4 size 931.51GiB used 280.00GiB path /dev/sdl
   devid5 size 1.82TiB used 1.17TiB path /dev/sdi
   devid6 size 1.82TiB used 823.03GiB path /dev/sdj
   devid7 size 698.64GiB used 47.00GiB path /dev/sdg
   devid8 size 1.82TiB used 1.18TiB path /dev/sda
   devid9 size 1.82TiB used 1.18TiB path /dev/sdb
   devid   10 size 1.36TiB used 745.03GiB path /dev/sdh

I added a couple disks, and then ran a balance operation, and that took about 3 
days to finish.  When it did finish, tried a scrub and got this message:

scrub status for 597ee185-36ac-4b68-8961-d4adc13f95d4
   scrub started at Sun Jun 26 18:19:28 2016 and was aborted after 01:16:35
   total bytes scrubbed: 926.45GiB with 18849935 errors
   error details: read=18849935
   corrected errors: 5860, uncorrectable errors: 18844075, unverified errors: 0

So that seems bad.  Took a look at the devices and a few of them have errors:
...
[/dev/sdi].generation_errs 0
[/dev/sdj].write_io_errs   289436740
[/dev/sdj].read_io_errs289492820
[/dev/sdj].flush_io_errs   12411
[/dev/sdj].corruption_errs 0
[/dev/sdj].generation_errs 0
[/dev/sdg].write_io_errs   0
...
[/dev/sda].generation_errs 0
[/dev/sdb].write_io_errs   3490143
[/dev/sdb].read_io_errs111
[/dev/sdb].flush_io_errs   268
[/dev/sdb].corruption_errs 0
[/dev/sdb].generation_errs 0
[/dev/sdh].write_io_errs   5839
[/dev/sdh].read_io_errs2188
[/dev/sdh].flush_io_errs   11
[/dev/sdh].corruption_errs 1
[/dev/sdh].generation_errs 16373

So I checked the smart data for those disks, they seem perfect, no reallocated 
sectors, no problems.  But one thing I did notice is that they are all WD Green 
drives.  So I'm guessing that if they power down and get reassigned to a new 
/dev/sd* letter, that could lead to data corruption.  I used idle3ctl to turn 
off the shut down mode on all the green drives in the system, but I'm having 
trouble getting the filesystem working without the errors.  I tried a 'check 
--repair' command on it, and it seems to find a lot of verification errors, but 
it doesn't look like things are getting fixed.
 But I have all the data on it backed up on another system, so I can recreate 
this if I need to.  But here's what I want to know:

1.  Am I correct about the issues with the WD Green drives, if they change 
mounts during disk operations, will that corrupt data?

I just wanted to chip in with WD Green drives. I have a RAID10 running on 6x2TB of 
those, actually had for ~3 years. If disk goes down for spin down, and you try to 
access something - kernel & FS & whole system will wait for drive to re-spin 
and everything works OK. I’ve never had a drive being reassigned to different /dev/sdX 
due to spin down / up.
2 years ago I was having a corruption due to not using ECC ram on my system and 
one of RAM modules started producing errors that were never caught up by CPU / 
MoBo. Long story short, guy here managed to point me to the right direction and 
I started shifting my data to hopefully new and not corrupted FS … but I was 
sceptical of similar issue that you have described AND I did raid1 and while 
mounted I did shift disk from one SATA port to another and FS managed to pick 
up the disk in new location and did not even blinked (as far as I remember 
there was syslog entry to say that disk vanished and then that disk was added)

Last word, you got plenty of errors in your SMART for transfer related stuff, 
please be advised that this may mean:
- faulty cable
- faulty mono controller
- faulty drive controller
- bad RAM - yes, mother board CAN use your ram for storing data and transfer 
related stuff … specially chapter ones.
It's worth pointing out that the most likely point here for data 
corruption assuming the cable and controllers are OK is during the DMA 
transfer from system RAM to the drive controller.  Even when dealing 
with really good HBA's that have an on-board NVRAM cache, you still have 
to copy the data out of system RAM at some point, and that's usually 
when the corruption occurs if the problem is with the RAM, CPU or MB.



2.  If that is the case:
   a.) Is there any way I can stop the /dev/sd* mount points from changing?  Or 
can I set up the filesystem using UUIDs or something more solid?  I googled 
about it, but found conflicting info

Don’t get it the wrong way but I’m personally surprised that anybody still 

Re: raid1 has failing disks, but smart is clear

[Corey Coughlin]

Hi Tomasz,
Thanks for the response!  I should clear some things up, though.

On 07/06/2016 03:59 PM, Tomasz Kusmierz wrote:

On 6 Jul 2016, at 23:14, Corey Coughlin  wrote:

Hi all,
Hoping you all can help, have a strange problem, think I know what's going 
on, but could use some verification.  I set up a raid1 type btrfs filesystem on 
an Ubuntu 16.04 system, here's what it looks like:

btrfs fi show
Label: none  uuid: 597ee185-36ac-4b68-8961-d4adc13f95d4
Total devices 10 FS bytes used 3.42TiB
devid1 size 1.82TiB used 1.18TiB path /dev/sdd
devid2 size 698.64GiB used 47.00GiB path /dev/sdk
devid3 size 931.51GiB used 280.03GiB path /dev/sdm
devid4 size 931.51GiB used 280.00GiB path /dev/sdl
devid5 size 1.82TiB used 1.17TiB path /dev/sdi
devid6 size 1.82TiB used 823.03GiB path /dev/sdj
devid7 size 698.64GiB used 47.00GiB path /dev/sdg
devid8 size 1.82TiB used 1.18TiB path /dev/sda
devid9 size 1.82TiB used 1.18TiB path /dev/sdb
devid   10 size 1.36TiB used 745.03GiB path /dev/sdh
Now when I say that the drives mount points change, I'm not saying they 
change when I reboot.  They change while the system is running.  For 
instance, here's the fi show after I ran a "check --repair" run this 
afternoon:


btrfs fi show
Label: none  uuid: 597ee185-36ac-4b68-8961-d4adc13f95d4
Total devices 10 FS bytes used 3.42TiB
devid1 size 1.82TiB used 1.18TiB path /dev/sdd
devid2 size 698.64GiB used 47.00GiB path /dev/sdk
devid3 size 931.51GiB used 280.03GiB path /dev/sdm
devid4 size 931.51GiB used 280.00GiB path /dev/sdl
devid5 size 1.82TiB used 1.17TiB path /dev/sdi
devid6 size 1.82TiB used 823.03GiB path /dev/sds
devid7 size 698.64GiB used 47.00GiB path /dev/sdg
devid8 size 1.82TiB used 1.18TiB path /dev/sda
devid9 size 1.82TiB used 1.18TiB path /dev/sdb
devid   10 size 1.36TiB used 745.03GiB path /dev/sdh

Notice that /dev/sdj in the previous run changed to /dev/sds.  There was 
no reboot, the mount just changed.  I don't know why that is happening, 
but it seems like the majority of the errors are on that drive.  But 
given that I've fixed the start/stop issue on that disk, it probably 
isn't a WD Green issue.




I added a couple disks, and then ran a balance operation, and that took about 3 
days to finish.  When it did finish, tried a scrub and got this message:

scrub status for 597ee185-36ac-4b68-8961-d4adc13f95d4
scrub started at Sun Jun 26 18:19:28 2016 and was aborted after 01:16:35
total bytes scrubbed: 926.45GiB with 18849935 errors
error details: read=18849935
corrected errors: 5860, uncorrectable errors: 18844075, unverified errors: 0

So that seems bad.  Took a look at the devices and a few of them have errors:
...
[/dev/sdi].generation_errs 0
[/dev/sdj].write_io_errs   289436740
[/dev/sdj].read_io_errs289492820
[/dev/sdj].flush_io_errs   12411
[/dev/sdj].corruption_errs 0
[/dev/sdj].generation_errs 0
[/dev/sdg].write_io_errs   0
...
[/dev/sda].generation_errs 0
[/dev/sdb].write_io_errs   3490143
[/dev/sdb].read_io_errs111
[/dev/sdb].flush_io_errs   268
[/dev/sdb].corruption_errs 0
[/dev/sdb].generation_errs 0
[/dev/sdh].write_io_errs   5839
[/dev/sdh].read_io_errs2188
[/dev/sdh].flush_io_errs   11
[/dev/sdh].corruption_errs 1
[/dev/sdh].generation_errs 16373

So I checked the smart data for those disks, they seem perfect, no reallocated 
sectors, no problems.  But one thing I did notice is that they are all WD Green 
drives.  So I'm guessing that if they power down and get reassigned to a new 
/dev/sd* letter, that could lead to data corruption.  I used idle3ctl to turn 
off the shut down mode on all the green drives in the system, but I'm having 
trouble getting the filesystem working without the errors.  I tried a 'check 
--repair' command on it, and it seems to find a lot of verification errors, but 
it doesn't look like things are getting fixed.
  But I have all the data on it backed up on another system, so I can recreate 
this if I need to.  But here's what I want to know:

1.  Am I correct about the issues with the WD Green drives, if they change 
mounts during disk operations, will that corrupt data?

I just wanted to chip in with WD Green drives. I have a RAID10 running on 6x2TB of 
those, actually had for ~3 years. If disk goes down for spin down, and you try to 
access something - kernel & FS & whole system will wait for drive to re-spin 
and everything works OK. I’ve never had a drive being reassigned to different /dev/sdX 
due to spin down / up.
2 years ago I was having a corruption due to not using ECC ram on my system and 
one of RAM modules started producing errors that were never caught up by CPU / 
MoBo. Long story short, guy here managed to point me to the right direction and 
I started shifting my data to hopefully new and not corrupted FS … but I was 
sceptical of 

Re: raid1 has failing disks, but smart is clear

[Tomasz Kusmierz]

> On 6 Jul 2016, at 23:14, Corey Coughlin  wrote:
> 
> Hi all,
>Hoping you all can help, have a strange problem, think I know what's going 
> on, but could use some verification.  I set up a raid1 type btrfs filesystem 
> on an Ubuntu 16.04 system, here's what it looks like:
> 
> btrfs fi show
> Label: none  uuid: 597ee185-36ac-4b68-8961-d4adc13f95d4
>Total devices 10 FS bytes used 3.42TiB
>devid1 size 1.82TiB used 1.18TiB path /dev/sdd
>devid2 size 698.64GiB used 47.00GiB path /dev/sdk
>devid3 size 931.51GiB used 280.03GiB path /dev/sdm
>devid4 size 931.51GiB used 280.00GiB path /dev/sdl
>devid5 size 1.82TiB used 1.17TiB path /dev/sdi
>devid6 size 1.82TiB used 823.03GiB path /dev/sdj
>devid7 size 698.64GiB used 47.00GiB path /dev/sdg
>devid8 size 1.82TiB used 1.18TiB path /dev/sda
>devid9 size 1.82TiB used 1.18TiB path /dev/sdb
>devid   10 size 1.36TiB used 745.03GiB path /dev/sdh
> 
> I added a couple disks, and then ran a balance operation, and that took about 
> 3 days to finish.  When it did finish, tried a scrub and got this message:
> 
> scrub status for 597ee185-36ac-4b68-8961-d4adc13f95d4
>scrub started at Sun Jun 26 18:19:28 2016 and was aborted after 01:16:35
>total bytes scrubbed: 926.45GiB with 18849935 errors
>error details: read=18849935
>corrected errors: 5860, uncorrectable errors: 18844075, unverified errors: > 0
> 
> So that seems bad.  Took a look at the devices and a few of them have errors:
> ...
> [/dev/sdi].generation_errs 0
> [/dev/sdj].write_io_errs   289436740
> [/dev/sdj].read_io_errs289492820
> [/dev/sdj].flush_io_errs   12411
> [/dev/sdj].corruption_errs 0
> [/dev/sdj].generation_errs 0
> [/dev/sdg].write_io_errs   0
> ...
> [/dev/sda].generation_errs 0
> [/dev/sdb].write_io_errs   3490143
> [/dev/sdb].read_io_errs111
> [/dev/sdb].flush_io_errs   268
> [/dev/sdb].corruption_errs 0
> [/dev/sdb].generation_errs 0
> [/dev/sdh].write_io_errs   5839
> [/dev/sdh].read_io_errs2188
> [/dev/sdh].flush_io_errs   11
> [/dev/sdh].corruption_errs 1
> [/dev/sdh].generation_errs 16373
> 
> So I checked the smart data for those disks, they seem perfect, no 
> reallocated sectors, no problems.  But one thing I did notice is that they 
> are all WD Green drives.  So I'm guessing that if they power down and get 
> reassigned to a new /dev/sd* letter, that could lead to data corruption.  I 
> used idle3ctl to turn off the shut down mode on all the green drives in the 
> system, but I'm having trouble getting the filesystem working without the 
> errors.  I tried a 'check --repair' command on it, and it seems to find a lot 
> of verification errors, but it doesn't look like things are getting fixed.
>  But I have all the data on it backed up on another system, so I can recreate 
> this if I need to.  But here's what I want to know:
> 
> 1.  Am I correct about the issues with the WD Green drives, if they change 
> mounts during disk operations, will that corrupt data?
I just wanted to chip in with WD Green drives. I have a RAID10 running on 6x2TB 
of those, actually had for ~3 years. If disk goes down for spin down, and you 
try to access something - kernel & FS & whole system will wait for drive to 
re-spin and everything works OK. I’ve never had a drive being reassigned to 
different /dev/sdX due to spin down / up. 
2 years ago I was having a corruption due to not using ECC ram on my system and 
one of RAM modules started producing errors that were never caught up by CPU / 
MoBo. Long story short, guy here managed to point me to the right direction and 
I started shifting my data to hopefully new and not corrupted FS … but I was 
sceptical of similar issue that you have described AND I did raid1 and while 
mounted I did shift disk from one SATA port to another and FS managed to pick 
up the disk in new location and did not even blinked (as far as I remember 
there was syslog entry to say that disk vanished and then that disk was added)

Last word, you got plenty of errors in your SMART for transfer related stuff, 
please be advised that this may mean:
- faulty cable
- faulty mono controller
- faulty drive controller
- bad RAM - yes, mother board CAN use your ram for storing data and transfer 
related stuff … specially chapter ones. 

> 2.  If that is the case:
>a.) Is there any way I can stop the /dev/sd* mount points from changing?  
> Or can I set up the filesystem using UUIDs or something more solid?  I 
> googled about it, but found conflicting info
Don’t get it the wrong way but I’m personally surprised that anybody still uses 
mount points rather than UUID. Devices change from boot to boot for a lot of 
people and most of distros moved to uuid (2 years ago ? even the swap is 
mounted via UUID now)

>b.) Or, is there something else changing my drive devices?  I have most of 
> drives on an LSI SAS 9201-16i card, is there something I need to 

raid1 has failing disks, but smart is clear

[Corey Coughlin]

Hi all,
Hoping you all can help, have a strange problem, think I know 
what's going on, but could use some verification.  I set up a raid1 type 
btrfs filesystem on an Ubuntu 16.04 system, here's what it looks like:


btrfs fi show
Label: none  uuid: 597ee185-36ac-4b68-8961-d4adc13f95d4
Total devices 10 FS bytes used 3.42TiB
devid1 size 1.82TiB used 1.18TiB path /dev/sdd
devid2 size 698.64GiB used 47.00GiB path /dev/sdk
devid3 size 931.51GiB used 280.03GiB path /dev/sdm
devid4 size 931.51GiB used 280.00GiB path /dev/sdl
devid5 size 1.82TiB used 1.17TiB path /dev/sdi
devid6 size 1.82TiB used 823.03GiB path /dev/sdj
devid7 size 698.64GiB used 47.00GiB path /dev/sdg
devid8 size 1.82TiB used 1.18TiB path /dev/sda
devid9 size 1.82TiB used 1.18TiB path /dev/sdb
devid   10 size 1.36TiB used 745.03GiB path /dev/sdh

I added a couple disks, and then ran a balance operation, and that took 
about 3 days to finish.  When it did finish, tried a scrub and got this 
message:


scrub status for 597ee185-36ac-4b68-8961-d4adc13f95d4
scrub started at Sun Jun 26 18:19:28 2016 and was aborted after 
01:16:35

total bytes scrubbed: 926.45GiB with 18849935 errors
error details: read=18849935
corrected errors: 5860, uncorrectable errors: 18844075, unverified 
errors: 0


So that seems bad.  Took a look at the devices and a few of them have 
errors:

...
[/dev/sdi].generation_errs 0
[/dev/sdj].write_io_errs   289436740
[/dev/sdj].read_io_errs289492820
[/dev/sdj].flush_io_errs   12411
[/dev/sdj].corruption_errs 0
[/dev/sdj].generation_errs 0
[/dev/sdg].write_io_errs   0
...
[/dev/sda].generation_errs 0
[/dev/sdb].write_io_errs   3490143
[/dev/sdb].read_io_errs111
[/dev/sdb].flush_io_errs   268
[/dev/sdb].corruption_errs 0
[/dev/sdb].generation_errs 0
[/dev/sdh].write_io_errs   5839
[/dev/sdh].read_io_errs2188
[/dev/sdh].flush_io_errs   11
[/dev/sdh].corruption_errs 1
[/dev/sdh].generation_errs 16373

So I checked the smart data for those disks, they seem perfect, no 
reallocated sectors, no problems.  But one thing I did notice is that 
they are all WD Green drives.  So I'm guessing that if they power down 
and get reassigned to a new /dev/sd* letter, that could lead to data 
corruption.  I used idle3ctl to turn off the shut down mode on all the 
green drives in the system, but I'm having trouble getting the 
filesystem working without the errors.  I tried a 'check --repair' 
command on it, and it seems to find a lot of verification errors, but it 
doesn't look like things are getting fixed.  But I have all the data on 
it backed up on another system, so I can recreate this if I need to.  
But here's what I want to know:


1.  Am I correct about the issues with the WD Green drives, if they 
change mounts during disk operations, will that corrupt data?

2.  If that is the case:
a.) Is there any way I can stop the /dev/sd* mount points from 
changing?  Or can I set up the filesystem using UUIDs or something more 
solid?  I googled about it, but found conflicting info
b.) Or, is there something else changing my drive devices?  I have 
most of drives on an LSI SAS 9201-16i card, is there something I need to 
do to make them fixed?
c.) Or, is there a script or something I can use to figure out if 
the disks will change mounts?
d.) Or, if I wipe everything and rebuild, will the disks with the 
idle3ctl fix work now?


Regardless of whether or not it's a WD Green drive issue, should I just 
wipefs all the disks and rebuild it?  Is there any way to recover this?  
Thanks for any help!



--- Corey
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