outcome of big rsync. Puzzling

[mlaks at verizon.net]

On Monday 20 December 2004 12:45 pm, John Van Essen wrote:
> Had you already run rsync before encountering that disk problem?
Thank You so much John, you clarified everything!
> Maybe the target has junk in it that you fixed/deleted on the source?
No, i did that a while ago (a month) and that old fsck.ext3 turns out to be a 
red herring.
> Are you running rsync with --delete?  It will remove leftover garbage.
No I ran it without delete. 
But my whole letter assumed that there was no circumstance that could lead my 
system to delete files. 
In fact, I discovered that there could be such a rare deletion triggering 
circumstance, that myself actually triggered by some changes I made to the 
system the day between the two rsyncs!! So in fact that one directory should 
have been smaller on the preimage! And it is.
> Add --dry-run to see what rsync would delete without actually doing it.
>
> The other three cases where the size is smaller by 4096 bytes are very
> likely from source directories that used to contain a larger number of
> files, but no longer do, so the target directory needs 1 fewer block
> to hold the entries for the current files.
Wonderful!! That explains it exactly!!! You are 100% right!!!! Thanks!!!! I 
didnt think of the 4096 as representing a block. And the same mechanism I 
mentioned above was active over here to cause an OLD delete of images,!!!
You are wonderful! And thank you, Wayne too! I am grateful to both of you. I 
will be playing with Wayne's method of working with the screen tonight! 
Thank you both!!!
Mitchell
>
>     John