[OpenAFS] Re: Moving large data from volume to volume

[Andrew Deason]

On Wed, 12 Oct 2011 11:51:42 +0200
"Mag. Mike B. Kerber" <michael.kerber@univie.ac.at> wrote:

> Hello!
> 
> While reorganising our afs tree layout i was wondering if there is a
> on-server possibility to move large data set from a volume to another
> one (both RW on the same server) without sending the data itself over
> the wire.

No (at least, not without fiddling with the internal on-disk
structures). However, there is some code for the functionality of
"splitting" a volume into two volumes at a directory boundary, though it
is not yet fully functional in the stock OpenAFS source. It doesn't seem
like it would be too difficult to add the opposite functionality:
merging two volumes together. If those two operations existed, you could
have a way to move data like that, although it is perhaps a bit clumsy.

Or we could just make an operation to move/copy a file from one volume
to another if they're on the same partition. But nothing exists like
that now. (Naively, it seems like RXAFS_Rename could be made to do this,
hmm...)

You can of course issue the move from a client running on the
fileserver, which may reduce some of the network overhead, but that's
still much slower than a rename().

> Judging from performance this seems to be what happens...

Yeah.

-- 
Andrew Deason
adeason@sinenomine.net