Backing up to an external FAT32 disk

[Liam Proven]

On 12/07/07, Nils Kassube <kassube at gmx.net> wrote:
> Liam Proven wrote:
> > I am trying to backup a 98% full RAID array (some 100GB of stuff) onto
> > a 400GB FAT32 USB2 external hard drive. I don't have space on the RAID
> > itself to create the archive, nor on my 3G root FS.
> >
> > I tried (in my /media directory, the mountpoint for both the RAID and
> > the USB drive):
> >
> > tar -cvf usbdrive/raid.tar raid/
> >
> > This worked but I forgot one detail. FAT32 has a max file size of
> > about 4G. So when the archive got to 4G, it barfed.
>
> Try this:
>
> tar c raid | split -d --suffix-length=3 --bytes=1000m - usbdrive/raid_
>
> That will give you files of 1000MB size with filenames usbdrive/raid_<nnn>
> with <nnn> being numbers counting from 001.
>
> You can test the archive with:
>
> cat usbdrive/raid_* | tar tv
>
> And you can restore a file with:
>
> cat usbdrive/raid_* | tar x <filename>

Thanks for that idea.

May I ask, though, why you don't use any of GNU tar's built-in
multivolume backup functionality? This way, the only valid archive is
the concatenation of all of them. If I were to lose one part, the
whole set would be invalid. Using tar's own switches to segment the
backup, each segment is a valid archive with its own header, so if I
lose one chunk, I only lose the data in that segment - the rest would
still be usable.

-- 
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