Re: [gentoo-user] SD memory card not erasing, even with dd.

[Dale]

William Kenworthy wrote:
>
> On 29/12/21 20:26, Michael wrote:
>> On Tuesday, 28 December 2021 20:21:32 GMT Dale wrote:
>>> Howdy,
>>>
>>> As some may recall, I have quite a few deer trail cameras that use SD
>>> memory cards.  On occasion some of the cards start acting weird.  I've
>>> got one that is really weird.  Usually I just replace them but this one
>>> is a bit of a puzzle I'd like to solve.  When it stopped working, it
>>> had
>>> a dozen or so short videos on it that are about 30MBs on average.  Some
>>> color and large, some black and white night vision and fairly small.
>>> When it stopped working, I tried to reformat the thing.  The files
>>> remained even after that.  I then ran dd and zeroed the thing, files
>>> still there even tho dd reported no problems.  I then used this GUI
>>> disk
>>> program that tests memory cards and it claims the card is fine.  It
>>> writes files to it, reads them back.  I also used it to reformat the
>>> card.  The original videos are still there.  Today I decided to play
>>> with it again.  I ran this dd command on the stick.
>>>
>>>
>>> root@fireball / # dd if=/dev/zero of=/dev/sdh bs=4K conv=notrunc
>>> oflag=direct status=progress
>>> 31907364864 bytes (32 GB, 30 GiB) copied, 3956 s, 8.1 MB/s
>>> dd: error writing '/dev/sdh': No space left on device
>>> 7791745+0 records in
>>> 7791744+0 records out
>>> 31914983424 bytes (32 GB, 30 GiB) copied, 3956.94 s, 8.1 MB/s
>>> root@fireball / #
>>>
>>>
>>> As you can see, no errors. It wrote zeros until it ran out of space.
>>> Guess what, the original videos are still on the card.  File listing:
>>>
>>>
>>> root@fireball / # ls -al /run/media/dale/2140-2E00/DCIM/100MEDIA/*
>>> -rw-r--r-- 1 dale users        0 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/AAAAAAAA.AAA
>>> -rw-r--r-- 1 dale users        0 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/BBBBBBBB.BBB
>>> -rw-r--r-- 1 dale users 14335272 May  2  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0823.AVI
>>> -rw-r--r-- 1 dale users 50843576 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0824.AVI
>>> -rw-r--r-- 1 dale users 53137560 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0825.AVI
>>> -rw-r--r-- 1 dale users 18398504 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0826.AVI
>>> -rw-r--r-- 1 dale users 18922808 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0827.AVI
>>> -rw-r--r-- 1 dale users 18332888 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0828.AVI
>>> -rw-r--r-- 1 dale users 18726200 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0829.AVI
>>> -rw-r--r-- 1 dale users 18332920 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0830.AVI
>>> -rw-r--r-- 1 dale users 18005288 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0831.AVI
>>> -rw-r--r-- 1 dale users 17612088 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0832.AVI
>>> -rw-r--r-- 1 dale users 17153336 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0833.AVI
>>> -rw-r--r-- 1 dale users 16694584 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0834.AVI
>>> -rw-r--r-- 1 dale users        0 May  6  2018
>>> /run/media/dale/2140-2E00/DCIM/100MEDIA/WGI_0835.AVI
>>> root@fireball / #
>>>
>>>
>>>
>>> The zero byte files are broken, my first clue way back that the card
>>> needed replacing.  I see no errors in dmesg or messages.  Usually the
>>> cards produce errors and it remounts read only.  Not in this case tho.
>>> Mount info:
>>>
>>>
>>> root@fireball / # mount | grep sdh
>>> /dev/sdh1 on /run/media/dale/2140-2E00 type vfat
>>> (rw,nosuid,nodev,relatime,uid=1000,gid=100,fmask=0022,dmask=0022,codepage=43
>>>
>>> 7,iocharset=iso8859-1,shortname=mixed,showexec,utf8,flush,errors=remount-ro,
>>>
>>> uhelper=udisks2) root@fireball / #
>>>
>>>
>>>
>>> In the past, I've at times been able to copy the files off other cards
>>> going bad but it stays read only.  Reformating fails etc etc.
>>> Sometimes, it just plain doesn't work.  Almost always tho I get a error
>>> of some kind in messages or dmesg if not both.  This one tho, it's just
>>> plain weird.  No errors but nothing removes the files either.  Oh, I've
>>> checked the lock button.  It's not locked.  It is shown that way in
>>> dmesg as well.
>>>
>>>
>>> [2592841.808336] sd 10:0:0:2: [sdh] Write Protect is off
>>>
>>>
>>>
>>> Obviously I'm not going to trust this thing.  It will end up in the
>>> trash but, does this make sense to anyone else?  Of all the ones I've
>>> worn out, this is the only one that behaves this way.  I'd at least
>>> expect the format to fail or it only mount read only.  At least some
>>> sort of error anyway.
>>>
>>> Thoughts?
>>>
>>> Dale
>>>
>>> :-)  :-)
>> I don't think I've come across something like this before.  In my
>> case data is
>> lost, occasionally irretrievably.
>>
>> I suppose something has switched blocks on the SD as immutable,
>> probably a
>> controller having a hiccup.
>>
>> You could try blkdiscard to erase blocks directly - but I haven't
>> tried this
>> on an SD.  I also haven't tried to know if it will work at all
>> hdparm's secure
>> deletion.
>>
>> However, the best option is to see if the OEM offers a reset app for
>> this
>> particular card and use that.
>
> I have a few SD cards as OS disks on raspberry pi, odroids etc. One
> has your symptoms like yours - read only when it says its in write
> mode.  Took two days after the last write to syslog to drop dead -
> just before Christmas too, luckily it was part of a moosefs cluster so
> I could leave it in maintenance mode without affecting service -
> replaced today.  No salvaging it unfortunately - also not the first
> one that I have had die like this.  I tested some others and have one
> thats really slow when dd'ing zeros to clear vacant space (I think
> that's redundant for SD cards, better to trim it?) before making a
> compressable backup image.  It also drops to RO with no errors in
> syslog before completing.  So I am down 2 cards and need to order some
> more spares before another fails :(
>
> BillK
>
>
>
>


So while rare, it's not just me.  ;-)  I've had cards fail by just plain
refusing not to mount at all, mounting read only and such.  I've never
had one to fail like this tho.  I guess if this was some sort of
sensitive files, I'd have to put it in a shredder or take a pair of
scissors to it.  LOL 

I ordered 6 new cards as replacements.  They came in yesterday.  Like I
said, I wouldn't trust that card even if it started working again.  So,
off to the trash the weird card goes.  Now I just have to wonder why dd
and such didn't report problems.  :/ 

Thanks to all for the info.  Interesting. 

Dale

:-)  :-)