I have this situation:

* `marcos`: home server, canonical repository with all my files
  (`group=backup`)
* `angela`: laptop, with a subset of the files (`group=manual`)
* `VHS`: backup external USB storage, should have a redundant copy of
  all files (`group=manual`)

directly connecting the external USB drive to `marcos` is annoying, so
I usually connect it to `angela` instead, which doesn't have all the
files.

This brings up the peculiar situation that I cannot actually backup
all the files to `VHS` from `angela`, without first copying them
locally.

I have a few issues with that:

 1. it fails silently: if I try to copy to `VHS` and the file is not on
    `angela`, it silently fails:
   
        [997]anarcat@angela:mp3$ git annex drop nothere
        (recording state in git...)
        [998]anarcat@angela:mp3$ git annex copy --to VHS nothere
        [999]anarcat@angela:mp3$ git annex find --in VHS nothere
        [1001]anarcat@angela:mp3$ git annex list nothere
        here
        |VHS
        ||htcones
        |||marcos
        ||||web
        |||||bittorrent
        ||||||htconesdumb
        |||||||
        ___X___ nothere
        [1002]anarcat@angela:mp3$
        
    this shouldn't silently fail to copy: it should warn me that it
    can't find a file to copy, at least.

 1. it takes up more disk space: i need to download all the missing
    files locally before I can transfer them to `VHS`. here's the way
    I make sure files are transfered properly on `VHS`:
   
        git annex copy --to VHS --not --in VHS
        git annex get --not --in VHS
        git annex copy --to VHS --not --in VHS
        git annex drop --not --in 'here@{yesterday}'
        
    the latter line is expecially problematic, because it is not
    accurate...

 1. it's slower: i need to write files locally before I can transfer
    them. ideally, those files would be streamed, or at least I would
    need to buffer locally only one file at a time and not the whole
    batch.

Maybe I am missing something obvious here and there are other ways of
doing this. I am running `6.20160902+gitgbc49d8a-1~ndall+1`.

I know I could setup `angela` to be in the `transfer` group, but then
files I don't want would end up stored on `angela`: files that are
missing from other remotes, for example. Even worse, some files I *do*
want could be candidates for removal on `angela` because they have
been propagated everywhere, whereas I have a select set of files
(hence `group=manual`) that are present in `angela` that I want to
stay there.

It seems to me at least #1 above should be fixed: `copy` shouldn't
succeed when it can't comply with the requested preferred content
expression.

Somehow, I expected this to work, and maybe that's the core issue here:

    git annex copy --from marcos --to VHS nothere

Thanks for considering this! -- [[anarcat]]