Information Technology Reference
Not so much data: If you have only a small amount of data to
back up but a truly humongous drive, you might feel that you'll
never fill all that space with backups, and that you might therefore
like to use some of it for something else. In that case, feel free
to make three (or more) partitions, with the first two sized as I
discussed in Decide on Capacity .
Bootable duplicates for multiple Macs: If you want to store
bootable duplicates for more than one Mac on a single drive, you'll
need a separate partition for each, as I discuss later in this chapter,
in Choose Local or Network Backups . Versioned backups for all
your Macs, however, can live on a single partition.
Configure Your Drive
Now that you have those two vital pieces of information—which
partition map scheme to use and how many partitions you need—
you have but to click a few buttons to configure your drive.
Warning! This procedure totally and irrevocably erases everything
on your external drive. You knew that, but this being a book about
backups, one can never have too many copies of crucial data!
Follow these steps:
1. If Disk Utility is not already running, open it now (you can find it
in /Applications/Utilities ).
2. In the list at left, select your external drive.
3. On the Partition pane, choose the number of partitions you want to
have from the Partition Layout pop-up menu. (Don't leave it set to
Current, even if you plan to keep the same number of partitions.)
4. Initially, the partitions will be sized equally. If you want them to be
differently sized, drag the divider bar between them to resize them.
5. Click Options. In the dialog that appears ( Figure 3 ), select the
scheme you want to use and click OK.