dump(8) using snapshot + "recommended" cache
RW
rwmaillists at googlemail.com
Sun Feb 1 10:31:34 PST 2009
On Sun, 1 Feb 2009 08:59:02 -0400 (AST)
Andrew Hamilton-Wright <andrewhw at ieee.org> wrote:
>
> Hi All;
>
> I regularly use dump(8) with snapshots to back up my server.
>
> While this seems to have been working perfectly well so far,
> upon (re)reading the man page for dump(8), I have noticed a
> somewhat scary pair of lines in the paragraph describing
> the option for -C <cachesize> (emphasis with stars mine):
>
> [Use of this option] will greatly improve performance
> at the cost of ***dump possibly not noticing changes in
> the file system*** between passes.
>
> ***It is recommended that you always use this option when
> dumping a snapshot.***
>
When you dump a snapshot there are, by definition, no changes between
passes. So it's saying that in that case there in no reason not to
cache.
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