Preparing for File System Backups

The preparation for backing up file systems begins with planning, which is described in Chapter 23, Backing Up and Restoring UFS 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 23, Backing Up and Restoring UFS 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 UFS File System Names

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 24-1 Finding File System Names

In this example, the file systems to be backed up are root (/), /usr, and 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/c0t0d0s7       /dev/rdsk/c0t0d0s7      /export/home    ufs     2       yes     -
/devices        -       /devices        devfs   -       no      -
sharefs -       /etc/dfs/sharetab       sharefs -       no      -
ctfs    -       /system/contract        ctfs    -       no      -
objfs   -       /system/object  objfs   -       no      -
swap    -       /tmp    tmpfs   -       yes     -

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

1. Become superuser or assume an equivalent role.
2. Estimate the size of the backup in bytes.

   # ufsdump [0]S file-system

   Use the S option to display the estimated number of bytes that are needed to do the backup if this is the first backup of the file system.

   Use the 0S option to display the estimated number of bytes that are needed to do the backup if this is not the first backup of the file system.

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

   For a list of tape capacities, see Table 23-5.

Example 24-2 Determining the Number of Tapes

In this example, the file system easily fits on a 150-MB tape.

# ufsdump S /export/home
178176