LVM data corruption

[Xen]

Forgot to say, for completeness:

Yes any PV with a single VG with a single LV will do.

Or conversely any VG with a single PV with a single LV will do.



1. Any type of LVM setup is probably going to be fine.

2. DD the entire disk including partitions including LVM partition (PV) 
is going to be fine.

3. Any LVM command is going to be fine ("lvs").



Number 3 above causes background "morphing" in case duplicate UUIDs are 
found.

This is the output:

> Found duplicate PV 3U9ac3Ah5lcZUf03Iwm0cgMMaKxdflg0: using /dev/sdb4 
> not /dev/sdc4

Or *can* be the output.

I have no error output.

I will just say that any report is just a report.



The police don't go tell you that they require a more detailed fully 
written report before they will investigate a burglary.

They consider it their own work to do this investigation.

When you report a crime, they take it from you from there. They do not 
require you to do their work. This would never work.

Then you can say "But this is how open source works" no, it is how open 
source "doesn't work".

It is when things "don't get fixed".

My report was nothing more than a report. It had no clear intent as to 
the desired outcome of that report.

Even if it does have some hidden or implied intent, that is basically an 
erroneous notion on my part that I consider myself your employee ;-).

The purpose of the report was to give information. Nothing else.

What anyone will do with it, is up to these people.

If I tell you a meteor fell from the sky yesterday, and you are 
interested in it, you will pursue it yourself.

If you are not interested, then it is not my job to make you interested.

You seem to be in the business of trying to escape responsiblity if 
nothing else.

Trying to find any reason to not do any work. If police worked like that 
they'd be fired.


"Yes ma'am we did not investigate your burglary because the neighbour 
girl didn't want to give enough detailed information, so we didn't do 
anything."

"We're sorry customer of ours, our systems fucked up your data because 
mister nobody that we don't know didn't give enough information so we 
couldn't investigate prior to this happening."

You'd be fired, probably.

It is just a means to not do your job, from my pov.

If you had it your way I would even do the development as well.

If you had it your way I would even do the uploading and the signing 
off, but you'd take credit for it.

I am sorry to be saying these things here, this was not my intent, 
because this gives rise to further discussion.

So I will end by trying to separate these two issues:



1. vgimportclone in 16.04 does not actually work.

I have no error output because I didn't save any and I am not going to 
repeat it.

It is for your information, not for mine.


But it fails it work if and when the above error message:

> Found duplicate PV 3U9ac3Ah5lcZUf03Iwm0cgMMaKxdflg0: using /dev/sdb4 
> not /dev/sdc4

causes the clone to be masked by the original.


In 16.10 it works because of whatever. There are stil error messages but 
it still works:

WARNING: PV 3U9ac3-Ah5l-cZUf-03Iw-m0cg-MMaK-xdflg0 on /dev/sdc4 was 
already found on /dev/sdb4. WARNING: PV 
3U9ac3-Ah5l-cZUf-03Iw-m0cg-MMaK-xdflg0 prefers device /dev/sdb4 because 
device is used by LV. WARNING: PV 3U9ac3-Ah5l-cZUf-03Iw-m0cg-MMaK-xdflg0 
on /dev/sdc4 was already found on /dev/sdb4. WARNING: PV 
3U9ac3-Ah5l-cZUf-03Iw-m0cg-MMaK-xdflg0 prefers device /dev/sdb4 because 
of previous preference.

This is the output of vgimportclone in 16.10 when this duplication has 
happened but it works.

I have no output saved, I have no output from 16.04.

You seem to want me to do all the work for you, because any bug report 
will also be followed up with endless requests for more information.

I consider that insincere and the information is already there.

Duplicate PVs cause mayhem and you can investigate this yourself if you 
want.

It does not take a lot of imagination to envision a setup in which this 
would happen.


The mechanism for the failure is also well-understood.

It is LVM seeing two PVs (with similar UUID) and then picking one of 
both. And it can do so runtime.

There is nothing hard to get about this and I'm sorry for allowing 
myself to be led on by this.

If someone gives you finger, you should not try to take the entire hand, 
arm and body. Of that person.

You should be content with the help you've been given.

I am writing now because I have a bit of time, but in general you cannot 
expect people to change their day because of you or for you.


You say I have expectatins towards developers. I have none.

You have expectations towards me.

If you do not want to fix it, that's fine.

It is your product, not mine.

You make money off it, not me, in that sense.

You don't want to fix your product, fine with me right. Bye.