Re: A question about subvolumes

[Austin S Hemmelgarn <ahferroin7@gmail.com>]

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On 07/05/2014 07:43 AM, Bob Williams wrote:
> On 05/07/14 07:27, Goffredo Baroncelli wrote:
>> On 07/04/2014 11:06 PM, Bob Williams wrote:
>>> On 04/07/14 21:38, Goffredo Baroncelli wrote:
> 
>>>
>>> Thank you, Goffredo. As the current /home/bob is not a
>>> subvolume, but a regular linux directory/folder, will the "cp
>>> --reflink" still carry the same speed advantage?
>>>
>>> In other words, using your example above, will this work:
>>>
>>> # cp --reflink -R normal_directory-A/* subvolume-B/ # rm -rf 
>>> normal_directory-A/
> 
>> Yes.
> 
>> If you want to move (or copy) files between subvolume, cp
>> --reflink is faster.
> 
> 
>> I have to point out that the "--reflink" is only an internal 
>> detail. The two file are logically separated: if you after the
>> copy change the source, the destination is unaffected.
> 
> Many thanks. Conversion of /home/bob to a subvolume completed
> uneventfully. :-) And very quickly, considering it is ~500GB. I have
> made a note of that --reflink option.
> 
> Bob
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I'm pretty certain that recent versions of the GNU Coreutils will
automatically try a reflink for cp if the underlying filesystem is
BTRFS.  I'm not 100% certain about this as I've just aliases cp to 'cp
--reflink=auto' on all my systems.


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