[linux-lvm] creating DD copies of disks

[Xen]

Xen schreef op 17-09-2016 16:16:

> I just won't be able to use the old system until I change it back.
> Time to test, isn't it.

Indeed both Linux and Windows have no issues with the new disk, I think.

I was making a backup onto a bigger-sized disk, but neither Windows nor 
Linux have an issue with it. They just see the old partition table of 
the old disk and are fine with that.

Now I only need to know if the Linux system will run with the new disk, 
but I'm sure there won't be issues there now. The system is not actually 
*on* that disk.

Call it a data disk for an SSD system.

So perhaps you can see why I would want to have the two disks loaded at 
the same time:

- if they work, I can copy data even after the DD (perhaps, to make some 
rsync copy as you indicate) but now I already have all the required 
structures (partition tables...) without any work.

- I wasn't actually yet done with the old disk. This was also just 
research. Better make a backup first before you finalize things. I want 
to do more work on the "old" system before I finalize things. But having 
a backup sitting there that I can use is a plus. Having to not be able 
to use both disks at the same time is a huge detriment. It is also not 
that hard now to change the system back but I still don't know how I can 
manually change the UUIDs that a VG/LV references. It is a huge plus if 
I can just exchange one PV with another at will.