System Administration Guide

Chapter 35 Restoring Files and File Systems (Tasks)

This chapter describes the procedures for restoring file systems.

This is a list of step-by-step instructions in this chapter.

This chapter describes how to use the ufsrestore(1M) command to restore files and file systems that were backed up using the ufsdump command. See Chapter 37, Copying UFS Files and File Systems (Tasks), for information about other commands you can use to archive, restore, copy, or move files and file systems.

Preparing to Restore Files and File Systems

The ufsrestore command copies files from backups created using the ufsdump command into the current working directory. You can use ufsrestore to reload an entire file system hierarchy from a level 0 dump and incremental dumps that follow it or to restore one or more single files from any dump tape. If ufsrestore is run by superuser, files are restored with their original owner, last modification time, and mode (permissions).

Before you start to restore files or file systems, you need to know:

Which tapes (or diskettes) you need
The raw device name for the file systems you want to back up
The type of tape drive you will use
The device name (local or remote) for the tape drive

Determining the Disk Device Name

If you have properly labeled your backup tapes, you should be able to use the disk device name (/dev/rdsk/devicename) from the tape label. See "How to Find File System Names" for more information.

Determining the Type of Tape Drive You Will Use

You must use a tape drive that is compatible with the backup media to restore the files. The format of the backup media determines which drive you must use to restore files. For example, if your backup media is 8-mm tape, you must use an 8-mm tape drive to restore the files.

Determining the Tape Device Name

You may have specified the tape device name (/dev/rmt/n) as part of the backup tape label information. If you are using the same drive to restore a backup tape, you can use the device name from the label. See Chapter 38, Managing Tape Drives (Tasks) for more information on media devices and device names.

Restoring Complete File Systems

Occasionally, a file system becomes so damaged that you must completely restore it. Typically, you need to restore a complete file system after a disk head crash. You may need to replace the hardware before you can restore the software. See Chapter 23, SPARC: Adding a Disk (Tasks), or Chapter 24, x86: Adding a Disk (Tasks) for information on how to replace a disk. Fully restoring a file system such as /export/home can take a lot of time. If you have consistently backed up file systems, you can restore them to their state at the last incremental backup.

Restoring Individual Files and Directories

This section describes how to restore individual files and directories using a local tape drive. See "How to Use a Remote Drive to Restore Files" for information on how to use a remote drive to restore files.

When you restore files in a directory other than the root directory of the file system, ufsrestore recreates the file hierarchy in the current directory. For example, if you restore files to /home1 that were backed up from /home/doc/books the files are restored in the /home1/doc/books directory.

When restoring individual files and directories, it is a good idea to restore them to a temporary location, such as the /var/tmp directory. After you verify them, you can move the files to their proper locations. You can restore individual files and directories to their original locations. If you do so, be sure you are not overwriting newer files with older versions from the backup tape.

Note -

Do not restore files in the /tmp directory even temporarily. The /tmp directory is usually mounted as a TMPFS file system and it does not support UFS file system attributes such as ACLs.

Using a Remote Drive to Restore Files

You can restore files from a remote drive by adding remote-host: to the front of the tape device name. Here is the syntax:

ufsrestore rf [user@]remote-host:/dev/rmt/unit filename

For example, to access /dev/rmt/0 on the system venus, type:

# ufsrestore rf venus:/dev/rmt/0 filename

Restoring File Systems

Things you need to know:

Which tapes have the files to be restored
The path name of the files to be restored

How to Determine Which Tapes to Use

Ask the user the date when the file or file system was lost, or the approximate date the files to be recovered were last modified.

Refer to your backup plan to find the date of the last backup that would have the file or file system on it.

To retrieve the most recent version of a file, work backward through the incremental backups from highest to lowest level and most recent to least recent, unless the user requests otherwise.

If you have online archive files, use the ufsrestore command to identify correct media.

# ufsrestore ta archive-name ./path/filename ./path/filename

`t`	List each file that appears on the tape.
`a`	Reads the table of contents from the online archive file instead of the tape.
`archive-name`	Identifies the online archive file name.
`./path/`filename	Identifies the file name(s) you are looking for on the online archive. If successful, `ufsrestore` will print out the inode number and file name. If unsuccessful, `ufsrestore` will print an error message.

Insert the media containing the backups in the drive and use the ufsrestore command to verify the correct media.
# ufsrestore tf device-name ./path/filename ./path/filename
Be sure to use the complete path for the filename(s). If a file is in the backup, its name and inode number is listed. Otherwise, a message says it is not on the volume.

If you have multiple dump files on the same tape, use the s /dev/rmt/n option to position the tape at the dump you want to use.
# ufsrestore xfs /dev/rmt/n tape_number

Example--Determining Which Tapes to Use

If you use ufsdump to dump the /usr file system, the table of contents lists only the files and directories under /usr. To see if /usr/bin/pwd is in the online archive, type:

# ufsrestore ta archive-name ./bin/pwd

To see if /usr/bin/pwd is on the backup tape, type:

# ufsrestore tf /dev/rmt/n ./bin/pwd

How to Restore Files Interactively

Become superuser.

Write-protect the tape.

Put the backup tape in the tape drive.

Change to a directory that will be used to restore the files temporarily.
# cd /var/tmp
If you want to restore the files to a different directory, substitute the directory name for /var/tmp in this step.

Use the ufsrestore command to start the interactive restoration.

Some informational messages and the ufsrestore> prompt are displayed.
# ufsrestore if /dev/rmt/n

Create a list of files to be restored.
1. List the contents of a directory.
  ufsrestore> ls directory
2. Change to a directory.
  ufsrestore> cd directory-name
3. Create a list of files and directories you want to restore.
  ufsrestore> add filename filename
4. [Optional] If you need to remove a directory or file name from the list of files to be restored, use the delete command.
  ufsrestore> delete filename

Turn on verbose mode to display the file names as they are being restored.
ufsrestore> verbose

Use the extract command after the list is complete.
ufsrestore> extract
The ufsrestore command asks you which volume number to use.

Type the volume number and press Return. If you have only one volume, type 1 and press Return.
Specify next volume #: 1
The files and directories in the list are extracted and restored to the current working directory.

To keep the mode of the current directory unchanged, enter n at the set owner/mode prompt.
set owner/mode for `.'? [yn] n

Quit the ufsrestore program.
ufsrestore> quit
The shell prompt is displayed.

Verify the files are restored.
1. List the restored files and directories.
  # ls -l
  A list of files and directories is displayed.
2. Check the list to be sure all the files and directories you specified in the list have been restored.
3. Move the files to the proper directories.

Example--Restoring Files Interactively

In this example, the files /etc/passwd and /etc/shadow are extracted from the backup tape.

# cd /var/tmp
# ufsrestore if /dev/rmt/0
ufsrestore> ls
.:
 .OWdefaults         bin         lib            sbin/
 .Xauthority         dev/        lost+found/    shared/
 .desksetdefaults    devices/    misc/          tmp/
 .fm/                etc/        mnt/           ufsboot
 .mailtool-init      export/     net/           usr/
 .openwin-init       home/       nfs/           var/
 .profile            hsfsboot    opt/           ws/
 .wastebasket/       kadb        proc/
 .xsun.pluto:0       kernel/
ufsrestore> cd etc
ufsrestore> add passwd shadow
ufsrestore> verbose
verbose mode on
ufsrestore> extract
Extract requested files
You have not read any volumes yet.
Unless you know which volume your file(s) are on you should start 
with the last volume and work towards the first.
Specify next volume #: 1
extract file ./etc/shadow
extract file ./etc/passwd
Add links
Set directory mode, owner, and times.
set owner/mode for `.'? [yn] n
ufsrestore> quit
#

How to Restore Specific Files

Become superuser.

Write-protect the tape for safety.

Put the backup tape in the tape drive.

Change to a directory for restoring files temporarily.
# cd /var/tmp
If you want to restore the files to a different directory, substitute the directory name for /var/tmp in this step.

Use the ufsrestore command to restore the file.

# ufsrestore xvf /dev/rmt/n filename ...

`x`	Tells `ufsrestore` to copy specific files or directories in the `filename` argument.
`v`	Displays the file names as they are restored.
`f /dev/rmt/n`	Identifies the tape device name.
filename ...	One or more individual file or directory names separated by spaces, for example: `./export/home/user1/mail` `./export/home/user2/mail`.

Type the volume number where files are located and press Return.
Specify next volume #: 1
The file is restored to the current working directory.

To keep the mode of the current directory unchanged, type n and press Return at the set owner/mode prompt.
set owner/mode for '.'? [yn] n

Verify the file is restored.
1. List the current directory.
  # ls -l filename
  A listing for the file is displayed.
2. Move the file to the proper directory.
  # mv filename /directory/filename

Example--Restoring Specific Files

In this example, the passwd and shadow files are restored to the /var/tmp directory.

# cd /var/tmp
# ufsrestore xvf /dev/rmt/0 ./etc/passwd ./etc/shadow
Verify volume and initialize maps
Media block size is 126
Dump   date: Wed Nov 06 15:21:10 1996
Dumped from: the epoch
Level 0 dump of / on pluto:/dev/dsk/c0t3d0s0
Label: none
Extract directories from tape
Initialize symbol table.
Warning: ./etc: File exists
Extract requested files
You have not read any volumes yet.
Unless you know which volume your file(s) are on you should start 
with the last volume and work towards the first.
Specify next volume #: 1
extract file ./etc/passwd
Add links
Set directory mode, owner, and times.
set owner/mode for `.'? [yn] n
# cd etc
#  mv passwd /etc
# mv shadow /etc
# ls -l etc

How to Use a Remote Drive to Restore Files

You can restore files from a remote drive by adding remote-host: to the front of the tape device name. Here is the syntax:

ufsrestore rf [user@]remote-host:/dev/rmt/n filename

For example, to access a remote tape drive /dev/rmt/0 on the system venus, type:

# ufsrestore rf venus:/dev/rmt/0 filename

How to Restore a Complete File System