full backup remotely?

[Tzafrir Cohen]

On Thu, Dec 31, 2009 at 12:35:48AM +0200, sammy ominsky wrote:
> On 31/12/2009, at 00:27, Hetz Ben Hamo wrote:
> 
> > doing the backup. dd is nice, but that will copy also the empty space
> > (although it won't have impact on the size of the backup, it will have an
> > impact on the time it takes). 
> 
> dd has a --sparse flag which makes it not copy empty space.

I don't see such a flag in the man page.

partimage avoids copying any "free" block (block marked as free by the
file system). If that block also happens to be zeroed out, dd is not
aware of such details. And frankly can't safely be aware of them if Hetz
want to copy a mounted partition.

Also note that if you use dd to copy a mounted partition, you copy
different parts of it in different times. This is tricky at best. Unless
you e.g. use an LVM with a snapshot.

tar (or any other backup of files) is safer. Even there you don't get a
complete snapshot of the system. But at least every file is valid.

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