Re: unexpected high fragmentation, any ideas?

[Steve Lord <lord@xxxxxxx>]

Marc Lehmann wrote:

> > The realtime allocator uses a different binary chop algorithm which while
> > wasteful, makes it very hard to fragment realtime files. Hmm, buffered works
>
> Hmm, is the realtime code ready for use then? I was under the (likely
> wrong) impression that the realtime code is not yet ready.

Let's see if someone answers that, I have no used the buffered over
realtime path, just seen the code.

> However, I *guess* I could easily live with, say, 128MB (or even
> 1GB) realtime extents and live with the internal frgamentation that
> will occur:  If my interpretation is right (not likely) the realtime
> allocator more-or-less treats these realtime extents as the basic unit of
> allocation, so internal fragmentation will be extremely high, but external
> fragmentation is low?
The realtime extent size is the unit of allocation in the realtime subvolume,
you still get larger extents than this, they are just always multiples of this.
I don't think you will see fragmentation at all.

Steve