dump(8) using snapshot + "recommended" cache

[Wojciech Puchar]

>
> 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.***
>
> Does anyone know what, exactly, this means?

no, in my experience it's no difference in speed with this enabled or not.