Backing Up Files and File Systems (Tasks)

This chapter describes the procedures for backing up file systems by using the ufsdump command.

For information on these procedures, see "Backing Up Files and File System (Task Map)".

For overview information about performing backups, see Chapter 45, Backing Up and Restoring File Systems (Overview).

For detailed information on ufsdump syntax, options, and arguments, see Chapter 49, UFS Backup and Restore Commands (Reference).

Backing Up Files and File System (Task Map)

Preparing for File System Backups

The preparation for backing up file systems begins with planning, which is described in Chapter 45, 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

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

• Finding 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

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--Finding File System Names

The file systems to be backed up in this example 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

1. Become superuser or assume an equivalent role.

2. Estimate the size of the backup in bytes.

   # ufsdump S file-system

   The S 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 45-5.

Example--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

Backing Up a File System

The following are general guidelines for performing backups:

• Use single-user mode or unmount the file system, unless you are creating a snapshot of a file system. For information about UFS snapshots, see Chapter 47, Using UFS Snapshots (Tasks).

• Be aware that the backing up of file systems when there are directory-level operations (such as creating, removing, and renaming files) and file-level activity occurring means that some data will not be included in the backup.

• You can run the ufsdump command from a single system and remotely back up groups of systems across the network through remote shell or remote login, and direct the output to the system on which the tape drive is located. (Typically, the tape drive is located on the system from which you run the ufsdump command, but it does not have to be.)

  Another way to back up files to a remote drive is to pipe the output from the ufsdump command to the dd command. For information about using the dd command, see Chapter 50, Copying UFS Files and File Systems (Tasks).

• If you are doing remote backups across the network, the system with the tape drive must have entries in its /.rhosts file for each client that will be using the drive. Also, the system that initiates the backup must be included in the /.rhosts file on each system that it will back up.

• To specify a remote tape device on a system, use the naming convention that matches the OS release of the system with the remote tape drive. For example, use the /dev/rst0 device for a remote drive on a system that is running the SunOS 4.1.1 release or compatible versions. Use the /dev/rmt/0 device for a system running the Solaris 9 release or compatible versions.

Note - Use the nisbackup command to back up a NIS+ master server. For information on using this command, see System Administration Guide: Naming and Directory Services (FNS and NIS+).

How to Backup a File System to Tape

The following steps provide the general steps for backing up file systems using the ufsdump command. The examples show specific uses of options and arguments.

1. Become superuser or assume an equivalent role.

2. Bring the system to run level S (single-user mode).

   # shutdown -g30 -y

3. (Optional) Check the file system for consistency.

   # fsck -m /dev/rdsk/device-name

   The fsck -m command checks for the consistency of file systems. For example, power failures can leave files in an inconsistent state. For more information on the fsck command, see Chapter 42, Checking UFS File System Consistency (Tasks).

4. If you need to back up file systems to a remote tape drive:

   1. On the system to which the tape drive is attached (the tape server), add the following entry to its /.rhosts file.

      host root

      The host entry specifies the name of the system on which you will run the ufsdump command to perform the backup.

   2. On the tape server, verify that the host added to the /.rhosts file is accessible through the name service.

5. Identify the device name of the tape drive.

   The default tape drive is the /dev/rmt/0 device.

6. Insert a tape that is not write-protected into the tape drive.

7. Back up file systems.

   # ufsdump options arguments filenames

   The following examples show how to use the most common ufsdump options and arguments:

   • "Example--Performing a Full Backup of root (/)"

   • "Example--Performing an Incremental Backup of root (/)"

   • "Example--Performing a Full Backup, Individual Home Directory"

   • "Example--Performing a Full Backup to Remote System (Solaris 9 Data to Solaris 9 System)"

   For other ufsdump options and arguments, see Chapter 49, UFS Backup and Restore Commands (Reference).

8. If prompted, remove the tape and insert the next tape volume.

9. Label each tape with the volume number, dump level, date, system name, disk slice, and file system.

10. Bring the system back to run level 3 by pressing Control-D.

11. Verify that the backup was successful.

    # ufsrestore tf device-name