Preparing to Do Backups

Preparing to back up file systems begins with planning, which is described in Chapter 33, Backing Up and Restoring File Systems (Overview) and covers choosing:

• A tape drive

• Which file systems to back up

• The type of backup (full or incremental)

• A backup schedule

This section describes other tasks you may 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 will 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
#
/proc             -                  /proc proc   -    no      -
swap              -                  /tmp  tmpfs  -    yes     -
/dev/dsk/c0t3d0s0 /dev/rdsk/c0t3d0s0 /     ufs    1    no      -
/dev/dsk/c0t3d0s1 -                  -     swap   -    no      -
/dev/dsk/c0t1d0s6 /dev/rdsk/c0t1d0s6 /usr  ufs    2    no      -
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 33-2 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