On Fri, Sep 21, 2012 at 6:31 AM, andy thomas <a...@time-domain.co.uk> wrote:
> I have a ZFS filseystem and create weekly snapshots over a period of 5 weeks
> called week01, week02, week03, week04 and week05 respectively. Ny question
> is: how do the snapshots relate to each other - does week03 contain the
> changes made since week02 or does it contain all the changes made since the
> first snapshot, week01, and therefore includes those in week02?
Every snapshot is based on the previous one and store only what is
needed to capture the differences.
> To rollback to week03, it's necesaary to delete snapshots week04 and week05
> first but what if week01 and week02 have also been deleted - will the
> rollback still work or is it ncessary to keep earlier snapshots?
No, it's not necessary. You can rollback to any snapshot.
I almost never use rollback though, in normal use. If I've
accidentally deleted or overwritten something, I just rsync it over
from the corresponding /.zfs/snapshots directory. Only if what I want
to restore is huge, rollback might be a better option.
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