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)
1. Prepare for file system backups
Identify the file systems, the type of backup, and the tape device to be used for the backups.
2. Determine the number of tapes needed to back up a file system
Determine the number of tapes that are needed for a full backup of a file system.
3. Back up your file systems
Perform a full backup of your file systems to get baseline copies of all files.
Perform an incremental backup of your file systems based on whether keeping copies of files that have changed on a daily basis is important at your site.
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
Display the contents of the /etc/vfstab file.
$ more /etc/vfstab
Look in the mount point column for the name of the file system.
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
Become superuser or assume an equivalent role.
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.
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.
Become superuser or assume an equivalent role.
Bring the system to run level S (single-user mode).
# shutdown -g30 -y
(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).
If you need to back up file systems to a remote tape drive:
On the system to which the tape drive is attached (the tape server), add the following entry to its /.rhosts file.
The host entry specifies the name of the system on which you will run the ufsdump command to perform the backup.
On the tape server, verify that the host added to the /.rhosts file is accessible through the name service.
Identify the device name of the tape drive.
The default tape drive is the /dev/rmt/0 device.
Insert a tape that is not write-protected into the tape drive.
Back up file systems.
# ufsdump options arguments filenames
The following examples show how to use the most common ufsdump options and arguments:
For other ufsdump options and arguments, see Chapter 49, UFS Backup and Restore Commands (Reference).
If prompted, remove the tape and insert the next tape volume.
Label each tape with the volume number, dump level, date, system name, disk slice, and file system.
Bring the system back to run level 3 by pressing Control-D.
Verify that the backup was successful.
# ufsrestore tf device-name