On 2/10/2010 7:21 PM, Daniel Carosone wrote:
On Wed, Feb 10, 2010 at 05:36:10PM -0600, David Dyer-Bennet wrote:
That's all about *ME* picking the suitable base snapshot, as I understand
it.
Correct.
I understood the recent reference to be suggesting that I didn't have
to, that zfs would figure it out for me. Which still appears to me to be
impossible; the receive node cannot communicate with the sending node
Correct.
There is, however, a wrinkle: if you have
s...@foo
s...@bar
s...@baz
d...@foo
d...@bar
and you do a send -RI s...@foo s...@baz
then you well send both @foo->@bar and @bar->@baz
However, the receiver will skip over the @foo->@bar part of the
stream, since it already has @bar, and pick up receiving @bar->@baz.
This doesn't save you read or network traffic, but does save you write
traffic and having to be exactly correct about picking the right base.
Ah. Okay, that's obviously technically possible (good thing, since it
apparently actually happens).
I wasn't considering that possibility because I was thinking of sending
everything *from the beginning*; the overhead of sending all that stuff
that hasn't changed in my situation is 5 or so orders of magnitude, not
to be seriously considered. But I see how it could indeed be useful in
theory to send just a *little* extra if you weren't sure quite what was
needed but could guess pretty closely.
Thanks!
--
David Dyer-Bennet, d...@dd-b.net; http://dd-b.net/
Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
Photos: http://dd-b.net/photography/gallery/
Dragaera: http://dragaera.info
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