Plans for BTRFS in Fedora

Casey Dahlin cdahlin at
Wed Feb 23 18:15:08 UTC 2011

On Wed, Feb 23, 2011 at 11:54:58AM -0600, Eric Sandeen wrote:
> On 2/23/11 11:42 AM, Jesse Keating wrote:
> > On 2/23/11 5:00 AM, Josef Bacik wrote:
> >> This would be a great thing in general since the default ext* image is
> >> shrunk down to be installed which creates a bad fs layout which has
> >> performance implications.
> > 
> > Can you expand upon this more?  The filesystem is shrunk down when the 
> > live image is built, but then once it is installed the fs is resized to 
> > fill out the physical disk / partition it is being installed to.
> Shrinking down the filesystem tends to scramble it a bit.  All the allocator
> decisions that were made based on fs size at the time of install go out the
> window as resize2fs fills in every hole it can find to maximally compress the
> fs.

Is there some sort of "sparsifying defrag" we could do after copying the image
over? The dd-based install is so fast that we could actually afford another
pass if we needed it IMHO.


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