Re: The --snaptime option

[Arthur Chance <freebsd@qeng-ho.org>]

On 04/28/10 21:27, Colin Percival wrote:
> Arthur Chance wrote:
> > I'm probably being stupid (not an uncommon occurrence) but I'm having
> > problems understanding the use of --snaptime. Specifically, do I need it
> > with ZFS snapshots, which seem to be different from UFS snapshots?
>
> Yes.
>
> > In search of more general enlightenment, can someone (Colin?) explain
> > what the race condition is that's referred to in the manual:

[Colin's explanation snipped]

> The --snaptime option allows Tarsnap to recognize situations where this might
> occur and make sure that it re-reads the file rather than assuming that it
> hasn't changed.
>
> Does that make sense?

Perfectly. Thanks.

Just to make sure I've got it right, I have to do

touch <snaptime-file>
zfs snapshot ...
tarsnap -c -f <archive> --snaptime <snaptime-file> ...

yes?