FFS fragments (was: RAID stripe size)

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

> The indirect blocks, and all blocks reached via an indirect block, 
> are all full blocks, never a fragment.
Oops, I didn't know that. That's very helpful.

> And fragments are only ever right at the end of a small file
That I /did/ know.

> Note that the numbers in parentheses [of the fsck output] are what is free
Oooooops. I never understood it that way.

> I believe the 2nd and 3rd numbers (used & free) are in units of 
> the fragment size (the minimum allocation size on the filesystem).
Must be that way, otherwise the numbers wouldn't make sense.
And I also didn't know that one.

> Perhaps surprisingly, the filesystem doesn't really bother keeping track
> of how much of anything is allocated
Yes, but fsck could.

> If read speed is more important than write speed, then bigger stripes
> make mode sense.
Why is that so?

In any case, for all practical reasons, my question in answered because 
the Borg repository holds mostly large files, which I learned are never 
fragmented.