Preparing to Do Backups

Preparing to back up file systems begins with planning, which is described in Chapter 42, Backing Up and Restoring File Systems (Overview) and includes choosing:

• A tape drive

• The file systems to back up

• The type of backup (full or incremental)

• A backup schedule

This section describes other tasks you might need to perform before backing up file systems, including:

• Finding names of file systems to back up

• Determining the number of tapes for a full backup

How to Find 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. You use the mount point in the mount point column when you back up the file system.

Example--Finding File System Names

$ more /etc/vfstab
#device           device             mount       FS   fsck  mount  mount
#to mount         to fsck            point       type pass at boot options
#
#/dev/dsk/c1d0s2  /dev/rdsk/c1d0s2   /usr         ufs    1      yes     -
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     -
mars:/share/kit   -                  /kit         nfs    -      yes     -
mars:/db/doc      -                  /db/doc      nfs    -      yes     -

How to Determine the Number of Tapes for a Full Backup

1. Become superuser.

2. Estimate the size of the backup in bytes by using the usfdump S command.

   # ufsdump S filesystem

   S	Displays the estimated number of bytes needed to do the backup.

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

   See Table 42-2 for a list of tape capacities.

Example--Determining Number of Tapes

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

# ufsdump S /export/home
489472