[Parted-maintainers] Bug#778712: libparted2: Breakage of RAID GPT header

Thu Feb 19 04:27:56 UTC 2015

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On 02/18/2015 05:15 PM, jnqnfe wrote:
>> Then you need to only manipulate md126 and ignore sdb and sdc.
>> Most of what you seem to be reporting involves looking directly
>> at the individual disks, which you must not do as that will
>> present a partial/corrupt view of the raid array.  In other
>> words, if the first few sectors of the raid array map to sdb,
>> then sdb will appear to have a partition table in its sector 0
>> that describes a disk that is twice the size, since this
>> partition table is actually describing the raid array and not the
>> individual disk.
> 
> I am not doing anything at all to the member disks, I am only 
> manipulating the array (mb126) and providing the ouput of fsdisk -l
> / parted -l (with unnecessary info about other disks removed).

All of the error messages shown in the logs you sent so far involve
the raw disks ( sdb, etc ) rather than the raid array.  You certainly
should not be running fdisk or parted on the raw disk, and responding
to the error messages by saying it should fix the problem ( since the
problem is only a result of looking at an individual disk instead of
the whole array ).

>> The one thing you mention that I can't write off as user error is
>> "but parted is not and seems to be forcibly applying what it
>> believes to be correct (ignoring the fact that it was only asked
>> to display info, not modify anything)".  Can you provide more
>> details here?  Exactly what command did you run and what changed
>> before vs. after?  Parted should not be modifying anything on the
>> disk unless you tell it to.  Normally it will throw a warning
>> telling you something is wrong with the disk and ask if you want
>> it to fix it and you have to answer "fix" for it to modify the
>> disk.
> 
> I did only exactly as described in my previous message, nothing
> more, nothing less.

You stated that parted modified the disk when you didn't tell it to,
but did not show exactly what command you gave that lead to this, and
more importantly, what if any, error messages parted threw and how you
responded to them.