Backup Yes again....

[Tony Nelson]

At 11:54 AM -0400 5/29/06, Franck Y  wrote:
>Hello,
>I used to have an ide VXA 1i tape backup on Win, but apparently it
>won't work on Linux...
>
>Since that i decide to buy a DVD burner and burn 3cds intead of a tape.
>For example I do the backup of a folder  around 11Go with tar and bz2
>but every time my archive is corrupted... Do you have any clue of what
>is happening ? Does my command is incorrect, i m running the Fedora
>FC4.
>My command is below
>
>tar -civf /media/administration.tar.bz2 /home/administration/

My limited experience suggests that using compression is a bad idea, as a
single error anywhere will ruin the rest of the backup (and possibly make
subsequent incremental backups useless).

(I'm unfamiliar with the syntax you use; does tar discover that it should
use the -j option by looking at the .bz2 extension?  I'd have expected "tar
-civjf".)

I have more difficulty with backups made to Plus media than with backups
made to Dash media.  I get more errors with Plus media, and programs (tar
and restore) have more trouble finding the EOT.  YMMV, different brand
media might make a difference, etc.

For tar I use, as root in one terminal:

    []# tar -clf /tmp/dvd -ML 4590200 /

In another terminal, each time tar wants to change tapes:

    []# growisofs -dvd-compat -Z /dev/dvd=/tmp/dvd

To verify afterward:

    []# tar -dMf /dev/dvd

If there is trouble finding the EOT, tar will say that the next tape is the
wrong tape.  Unfortunately, the problem was in finding the end of the
previous one.  My workaround is to copy each DVD into a temp file, with:

    []# dd if=/dev/dvd of=/tmp/dvd bs=2048 count=2295100

Run tar in another terminal:

    []# tar -dMf /tmp/dvd
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