setup-storage fails on blank disk

[Andreas Heinlein]

Am 03.01.2018 um 17:28 schrieb Holger Parplies:
> Hi,
>
> Andreas Heinlein wrote on 2018-01-03 13:53:40 +0100 [setup-storage fails on blank disk]:
>> [...]
>> I have encountered a problem with setup-storage which occurs only when
>> the disk is blank, i.e. wiped with nwipe/dban or brand new. It then
>> fails on creating the LVM; running 'pvcreate' returns 'cannot open
>> /dev/sda5 exclusively'.
> this is probably unrelated, but is there any reason to put the LVM PV inside
> a "logical" volume? DOS extended partitions seem to be the worst hack ever
> invented to get around a limitation in a bad design, yet they repeatedly
> and apparently unnecessarily pop up in quoted disk_configs:
>
>> [...]
>> This is your disk_config file:
>> # generic disk configuration for one small disk
>> # disk size from 500Mb up to what you can buy today
>> #
>> # <type> <mountpoint> <size in mb> <fstype> <mount options>  [extra options]
>>
>> disk_config disk1 disklabel:msdos bootable:1 preserve_lazy:6 align-at:1M fstabkey:uuid 
>> primary  /boot	       300	ext4	rw	createopts="-O ^64bit,^metadata_csum"
>> logical  -	       29500-30000	-	-
>> logical  /media/daten  1024-	ext4	acl	createopts="-O ^64bit,^metadata_csum -L Daten"
> I count three partitions, which would work perfectly with primary partitions
> (furthermore, you are using LVM to have an arbitrary number of named and
> dynamic "volumes" (i.e. partitions) anyway, so if you needed more, LVM would
> be the superior mechanism; of course, your specific requirements may vary).
> Ok, you are preserving a logical partition, so in this particular case you'd
> actually need to stick with logical partitions, but the partition in question
> is ext4, not FAT-based, so it doesn't appear to be a legacy Windoze issue.
>
> My point: am I missing something, and there is some obscure benefit of putting
> an LVM container within an extended-partition-container (such as hiding it
> from something), or is it simply a common misconception that you for some
> reason cannot or should not put an LVM PV (or even several individual native
> Linux partitions - such as /, /var and /tmp) into primary partitions -
> assuming you only need upto four of them (and, obviously, assuming you are
> still using MSDOS partition tables)?
>
> Or, differently: for a *blank disk*, you obviously won't be preserving sda6,
> and you probably aren't referencing it by partition number ("fstabkey:uuid"),
> so does using 'primary' instead of 'logical' for all three partitions change
> anything concerning the error you are experiencing?
>
> Hope that helps someone (perhaps me ;-) ...
>
> Regards,
> Holger
Hello,

yes, you are right - in some way, this *is* a legacy windows issue that
has developed over time. In fact, the preserved partition once was a FAT
partition as long as we had dualboot installations on these machines. We
finally removed the dualboot two or three years ago and chose to format
this partition ext4 instead. Why we didn't move to primary partitions or
put it within the LVM at that time - I don't know.

On the other hand, up to now we had no problems with that, so no urge to
change anything. If you think it might help, I could try changing this.

Bye,
Andreas