Preparing for File System Backups

The preparation for backing up file systems begins with planning, which is described in Chapter 22, Backing Up and Restoring File Systems (Overview) and includes choosing the following:

• The file systems to back up

• The type of backup (full or incremental) to perform

• A backup schedule

• A tape drive

For more information, see Chapter 22, Backing Up and Restoring File Systems (Overview).

This section describes two other tasks you might need to perform before you back up file systems:

• Finding the names of file systems to back up

• Determining the number of tapes that are needed for a full backup

How to Find File System Names

Steps

1. Display the contents of the /etc/vfstab file.

   $ more /etc/vfstab

2. Look in the mount point column for the name of the file system.

3. Use the directory name listed in the mount point column when you back up the file system.

Example 23–1 Finding File System Names

In this example, the file systems to be backed up are root (/), /usr, /datab, and /export/home.

$ more /etc/vfstab
#device           device             mount        FS   fsck mount   mount
#to mount         to fsck            point        type pass at boot options
#
fd                -                  /dev/fd      fd    -    no      -
/proc             -                  /proc        proc  -    no      -
/dev/dsk/c0t0d0s1 -                  -            swap  -    no      -
/dev/dsk/c0t0d0s0 /dev/rdsk/c0t0d0s0 /            ufs   1    no      -
/dev/dsk/c0t0d0s6 /dev/rdsk/c0t0d0s6 /usr         ufs   1    no      -
/dev/dsk/c0t0d0s5 /dev/rdsk/c0t0d0s5 /datab       ufs   2    yes     -
/dev/dsk/c0t0d0s7 /dev/rdsk/c0t0d0s7 /export/home ufs   2    yes     -
swap              -                  /tmp         tmpfs -    yes     -

How to Determine the Number of Tapes Needed for a Full Backup

Steps

1. Become superuser or assume an equivalent role.

2. Estimate the size of the backup in bytes.

   # ufsdump S file-system

   The S option displays the estimated number of bytes that are needed to do the backup.

3. Divide the estimated size by the capacity of the tape to see how many tapes you need.

   For a list of tape capacities, see Table 22–5.

Example 23–2 Determining Number of Tapes

In this example, the file system of 489,472 bytes easily fits on a 150-Mbyte tape.

# ufsdump S /export/home
489472