On 01.06.2015 15:03, Neal Becker wrote:
> So I think what I need to do is:
> 
> 1. boot off some rescue media
> 2. mount the target btrfs volume (e.g., /mnt/sysimage/root)
> 3. mv exising home (mv /mnt/sysimage/home /mnt/sysimage/oldhome)
> 4. create new subvolume (btrfs subvolume create /mnt/sysimage/home)
> 5. move all the files from /mnt/sysimage/oldhome /mnt/sysimage/home - not 
> sure easiest way to do this step
> 6. edit /mnt/sysimage/etc/fstab to mount new /home
> 
> I have another machine, setup more or less this way:
> UUID=7246327b-1905-4fe2-9b6b-b9376017264f /                       btrfs   
> subvolid=5,subvol=root00 0 0
> UUID=2c04be93-34c1-4016-ba41-60fd9fd90616 /boot                   ext4    
> defaults        1 2
> UUID=7246327b-1905-4fe2-9b6b-b9376017264f /home                   btrfs   
> subvol=home     0 0
> 
> 
> 
> Vytautas D wrote:
> 
>> as far as I know, you can't do this, you need to temporary move /home
>> somewhere else, create /home subvolume and copy everything back.
>>
>> -
>> Vytas
>>
>> On Mon, Jun 1, 2015 at 1:36 PM, Neal Becker <ndbecker2@gmail.com> wrote:
>>> I have everything under /:
>>>
>>> sudo btrfs subvolume list /
>>> ID 257 gen 65795 top level 5 path root
>>>
>>> I want to move /home onto it's own subvolume.  I hope I can do this while
>>> the root device is mounted.
>>>
>>> What is the procedure?
>>>
>>> I tried first to create a subvolume for /home at the top-level, but
>>> couldn't figure out the syntax:
>>>
>>> [nbecker@nbecker2 ~]$ sudo btrfs subvolume create /home
>>> [sudo] password for nbecker:
>>> ERROR: '/home' exists
>>>


i think you can speed up step 5 there by not using mv but cp
--reflink=auto and deleting the old copy once you are done.  reflinks
are shared between subvolumes.

justus