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(tar.info)Inc Dumps

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Using `tar' to Perform Incremental Dumps
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     _(This message will disappear, once this node revised.)_

   Performing incremental dumps is similar to performing full dumps,
although a few more options will usually be needed.

   A standard scheme is to do a _monthly_ (full) dump once a month, a
_weekly_ dump once a week of everything since the last monthly and a
_daily_ every day of everything since the last (weekly or monthly) dump.

   Here is a sample script to dump the directory hierarchies `/usr' and
`/var'.

     #! /bin/sh
     tar --create \
      --blocking-factor=126 \
      --file=/dev/rmt/0 \
      --label="`hostname` /usr /var `date +%Y-%m-%d`" \
      --listed-incremental=/var/log/usr-var.snar \
      --verbose \
      /usr /var

   This script uses the file `/var/log/usr-var.snar' as a snapshot to
store information about the previous tar dump.

   The blocking factor 126 is an attempt to make the tape drive stream.
Some tape devices cannot handle 64 kB blocks or larger, and require the
block size to be a multiple of 1 kB; for these devices, 126 is the
largest blocking factor that can be used.