Technical Snapshot questions

[David Gilbert]

I've been using snapshots as the lowest level of my backup system on
my laptop for awhile.  I'm pretty sure that it's caused a little extra
instability ... but I don't have hard evidence yet... it could just be
normal -CURRENT churn... but that's not my question.

If I have a large number of sparse files ... and I take a snapshot
... and then I fill in a previously unfilled block in the sparse file,
do I have now two completely separate sparse files ... one in the
snapshot and one in the filesystem proper ... or does the added block
just merge itself in.  If it's the latter, how much overhead would
this cause?  The sparse files are about 1G in size with most degrees
of fullness being represented.

That question brought to mind another: Does the inode of either the
"real" file or the snapshot version of the file change?  Or is the
inode space of the snapshot separate from the filesystem proper?

Dave.

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|David Gilbert, Independent Contractor.       | Two things can only be     |
|Mail:       dave at daveg.ca                    |  equal if and only if they |
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