default file system, was: Comparison to Workstation Technical Specification

[Ric Wheeler]

On 02/28/2014 06:20 AM, Chris Murphy wrote:
> On Feb 26, 2014, at 12:53 PM, Michael Cronenworth <mike at cchtml.com> wrote:
>
>> Chris Murphy wrote:
>>> by default we put ext4 on LVM
>> The tool works in this use-case unless something has broken it recently.
> It can be done, the convert tool should work, and Btrfs should work on any device mapper instance. However…
>
> In the context of the default ext4+LVM layout the conversion still means separate /boot, /, and /home file systems. A major benefit of the Btrfs layout is these are subvolumes, which instead draw space from one volume pool. And that's lost with a conversion strategy. It also means going from a Fedora "standard" layout to a distinctly non-standard one because our Btrfs layout isn't like the result you'd get from what you're talking about.
>
>
> Chris Murphy

That is not much different than what happens with device mapper - the new device 
mapper has a shared exception store that can be used to share physical space 
across multiple real file systems. Note that the real file systems can be thinly 
provisioned or fully provisioned, but if you start full, you will need to add 
space to grow (unless you shrink something).

btrfs subvolumes are kind of hackish to be honest, they are in many ways like 
real file systems.

ric