Convert ext4 lvm to normal ext4 partition

Michael Miles mmamiga6 at gmail.com
Fri Nov 12 18:34:09 UTC 2010


Patrick O'Callaghan wrote:
> On 12/11/10 1:13 PM, Michael Miles wrote:
>> Considering that the LVM is a ext4 Virtual partition it seems to me 
>> that it would be easy to convert but there is no such beast out there
>> Lots of stuff for converting ext3 to ext4 but nothing for what I need.
>
> This is pure speculation on my part, but I'm guessing one reason it's 
> hard is that the LVM layer knows nothing about the ext4 layer. The 
> ext4 layer contains lots of metadata (inodes, freelists, etc.) which 
> includes pointers to disk sectors or extents. In a physical partition 
> these point to real disk addresses but in an LVM partition they are 
> virtual (compare real with virtual memory for an analogy). From LVM's 
> viewpoint the entire ext4 fs is just disk sectors with random binary 
> data. The fact that some of this stuff is fs metadata and some isn't 
> means that a conversion tool would need to understand the ext4 
> metadata to convert it. Of course if it's ext3 or xfs or btrfs etc. 
> then the same applies, with different rules for each one.
>
> Worse still, if you want a in-place conversion you have to be able to 
> do this in such a way that it's recoverable even after a hard system 
> crash in the middle of the conversion. And if you don't need it 
> in-place, you already have the solution as said before.
>
> Just my 2 cents.
>
> poc
Agreed, I am just really surprised that Fedora would adopt this method 
of storage as it slows down the drive by a huge margin.
That reason alone would say to me' No, don't want this"


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