9    Administering the Archiving Services

One of the more common tasks of a system administrator is helping users recover lost or corrupted files. To perform that task effectively, you must set up procedures for backing up files at frequent and regular intervals. This chapter describes how you use resident commands and utilities to back up (archive) and restore files and directories.

Design and implement a disaster recovery plan that describes how you intend to restore your entire operating system and user files to normal operations in the event of a catastrophic failure. This chapter does not describe the disaster recovery process, because it is often very specific to site operations and business requirements. However, backup operations are an important component of such a plan.

The following topics are included in this chapter:

9.1    Understanding Backup Tasks

This chapter describes basic backup operations for a system using the UFS file system. You also may need to use other backup and restore utilities if any of the following conditions apply to your local system:

The main tasks comprising backup and restore operations are:

9.2    Backing Up Data and System Files

For basic backup, you can use the dump and restore commands. See dump(8) for full details of all command options that are supported. The operating system also provides graphical and command line tools for archiving and for creating a bootable tape of the standalone system (SAS).

Prevention of data loss is an important part of any backup and recovery strategy. There are many tools for system monitoring that you can configure to help prevent situations that may result in data loss. For example, some systems support environmental monitoring, and there are tools to test and exercise peripherals. There are also the event and error logging systems that you can configure to monitor the system for priority events such as a backup failure. See Chapter 13 for information on using the Event Manager to set up the event reporting strategy for your system and site. You can use the Event Manager to report on the success of your backups, ensuring that you do not miss a scheduled backup event.

It is important that all the files on your system, user files and system files, are protected from loss. Back up your entire system, including the system software. Many system files are static; that is, after you install them they remain unchanged. Therefore, you do not need to back up system files as frequently as data files. Incremental backups are also possible, and you may consider implementing them if your data changes significantly in a short period.

Each file system backup is a single process. To ease the backup process, organize your file systems so that dynamic files are on file systems that you back up regularly and static (system or program) files are on file systems that you back up occasionally. You may find that you have dynamic files on file systems that you back up occasionally. If this happens and you need to back them up regularly, just prior to performing a backup, copy the frequently changing files to systems that you back up regularly. This allows you to back up those files without backing up an entire file system. You can write shell scripts to automate these tasks and use the cron command to automate the schedule. See cron(8) for more information.

9.3    Choosing a Backup Schedule

To decide how often to back up each file system, consider the balance between the potential loss of user time and data and the time it takes you to perform backups. Ask yourself the question, "How much information can I afford to lose?" The answer to this question helps you determine your minimum backup interval. On most systems the backup interval is daily, but you can choose any other interval.

It is not necessary to back up all the files in a file system at each backup. Back up only those files that changed since the previous backup; this is called an incremental backup. Using the dump and restore commands, you can perform up to nine levels of incremental backups. For example, while a level 0 dump backs up an entire file system, a level 1 dump backs up only those files changed since the last level 0 dump, and a level 7 dump backs up only those files changed since the last lower level dump.

To integrate incremental backups into your file backup schedule, you need to balance the time and tape space required for backup against the amount of time it could take you to restore the system in the event of a system failure. For example, you could schedule backup levels following the 10-day sequence:

[0 1 2 3 4 5 6 7 8 9]

On the first day you save an entire file system (level 0). On the second day you save changes since the first backup and so on until the eleventh day when you restart the sequence. This makes the amount of time spent and data saved on each backup relatively small each day except the first; however, if a system failure on the tenth day requires that you restore the entire system, you must restore all ten tapes.

Most systems follow some variant of the common Tower of Hanoi backup schedule. Once monthly you make a level 0 dump to tape of all the file systems that you backup regularly. Once weekly, you make a level 1 dump to start a daily sequence of:

[...3 2 5 4 7 6 9 8 9 9 ...]

If you do backups only once a day on the weekdays, you end up with a monthly backup schedule as follows:

[0 1 3 2 5 4 1 3 2 5 4 ...]

This schedule, although slightly complex, requires that you restore at most four tapes at any point in the month if a system failure corrupts files. Of course, doing a level 0 dump daily requires that you restore at most one tape at any point, but requires a large amount of time and tape storage for each backup. On most days in the Tower of Hanoi schedule, you require very little time and tape storage space for the backup.

9.4    Backup Methods

Depending on your needs and your local system configuration, there are several options for backing up data, as follows:

Some tools provide you with additional options when you run them as superuser (root).

9.5    Preparing to Perform a Backup

The following sections contain information that you may need to prepare for a backup. Also included is a list of utilities that can assist you in preparing for a backup, and a list of prerequisite tasks.

Chapter 6 contains information on the UFS file system. The Hardware Management manual contains information on using disk and tape devices and on determining which disk and tape devices you want to back up. Also, see the information about the cron command in Chapter 3 for information on scheduling regular backups. The following sections contain other information that you may need to perform a backup:

9.5.1    Related Documentation

Additional documentation on using the backup utilities is available in manuals, reference pages, and online help.

9.5.1.1    Manuals

These manuals also provide useful information for archival services.

9.5.1.2    Reference Pages

Each utility has its own reference page that describes how to invoke the utility and the available options for that utility.

The following reference pages provide information on the basic utilities for dumping file systems to tape and restoring them back to disk:

These reference pages provide information on the basic utilities for creating and manipulating archive files:

The following reference pages provide information on the bootable tape interfaces:

The following reference pages provide information on creating cron entries for backup scripts that execute at specific dates and times.

The mcutil(1) reference page describes the media changer manipulation utility.

9.5.1.3    Online Help

Both the Archiver and Bootable Tape graphical user interfaces provide online help that describes your options and defines what data you can enter into the data fields in each window.

9.5.2    System Files

Apart from the file system that you specify and the archive files created, the following files are used or created when you create backups:

9.5.3    Related Utilities

The following utilities are useful when performing backups:

SysMan Station

The SysMan Station provides a graphical view of the storage devices available on the system. Use this interface to help you identify disk and tape devices and find their device names.

CDE Disk Usage Manager

The CDE Application Manager — Desktop_Tools folder provides a Disk Usage tool that runs the du command and returns statistics on disk usage. Use the Folder Size option to examine the size (in blocks) of any directory, such as /usr/users. Command line utilities du and df provide the same data.

CDE Application Manager

DailyAdmin folder provides the System Information interfaces, a graphical view of system resources such as file space usage. You can set this monitor to flash a visual warning when your preset file space limits are exceeded. You can also use the SysMan Station to monitor file systems as described in Chapter 1.

Event Manager

Provides a way of monitoring file system limits and alerts you of problems or can automatically start backups and cleanup of file systems.

dsfmgr and hwmgr

The command line interfaces dsfmgr and hwmgr enable you to query the system for information about devices, such as device names and disk partition size.

You can get information from the Disk Configuration GUI, which you can invoke from CDE Application Manager - Configuration folder, or from the SysMan Menu. This interface provides size information in megabytes, bytes, and blocks. (The disklabel command provides a command line disk configuration interface).

9.5.4    Prerequisite Tasks

The following prerequisite tasks apply to all the backup methods:

9.6    Using the dump Command

The dump command copies all designated file systems or individual files and directories changed after a specified date to a file, pipe, magnetic tape, disk, or diskette. See the AdvFS Administration manual for information on copying AdvFS file systems. You must have superuser privileges to use the dump command.

Note

To produce valid backups on a file system, you must back up a file system while it is inactive. It is recommended that you unmount the file system and examine it for consistency. As an added precaution, put the system into single-user mode before starting your backup operations. This is not true for AdvFS.

9.6.1    Performing a Full Backup

Set up a schedule for performing a full backup of each file system on your entire system, including all the system software. A conservative schedule for full system backups is to do one with each normal level 0 dump (using Tower of Hanoi, once a month), but you can set any schedule you like within the reliability of your storage media, which is about two years for magnetic tapes. To back up your file system, use the dump command. See dump(8) for a description of the command options that you use to specify the characteristics of the tape device, such as block size, tape storage density, and tape length. Specify the file system with a full pathname when you use the dump command. The dump command can back up only a single file system at a time, but there may be several dump processes simultaneously writing files to different tape devices.

The following list describes the most commonly used options to the dump command:

-integer

Specifies the dump level as an integer (0-9). A dump level of 0 causes a full dump of the specified file system. All other dump levels cause an incremental backup. That is, only files that have changed since the last dump of a lower dump level are backed up. The /etc/dumpdates file contains a record of when the dump command was used on each file system at each dump level. The -u option to the dump command updates the dumpdates file.

-f dump_file

Writes the dump to the device specified by dump_file instead of to the default device, /dev/tape/tape0_d0. If you specify the dump_file as a dash ( - ), the dump command writes to the standard output.

-u

Updates the /etc/dumpdates file with the time of the dump and the dump level for the file system in the backup. You use this file during incremental dumps (by using the dump level option) to determine which files have changed since a particular dump level. You can edit the /etc/dumpdates file to change any record or fields, if necessary. See dump(8), which describes the format of this file.

To back up your entire file system to the default backup device, use the dump command for each file system on your machine. The dump -0u command option causes a level 0 dump and updates the /etc/dumpdates file with the time and date of the backup for each file system. This creates an initial point on which to base all future incremental backups until the next full or level 0 dump. Each file system must be backed up individually.

For example, if you want to perform a level 0 dump of the root, /usr, and /projects file system partitions, follow these steps:

  1. To back up the root file system:

    1. Load a tape into your tape drive.

    2. Enter: 

      # dump -0u /

    3. Remove the tape from your tape drive after completing the backup.

  2. To back up the /usr file system:

    1. Load a new tape into your tape drive.

    2. Enter: 

      # dump -0u /usr

    3. Remove the tape from your tape drive after completing the backup.

  3. To back up the /projects file system:

    1. Load a new tape into your tape drive.

    2. Enter: 

      # dump -0u /projects

    3. Remove the tape from your tape drive after completing the backup.

You can either back up each file system on an individual tape, or you can back up multiple file systems on one tape by specifying the no-rewind device, /dev/ntape/tape0_d0, as the output device. The following examples show the root, /usr, and /projects file systems being backed up on one tape: 

# dump -0uf /dev/ntape/tape0_d0 /
# dump -0uf /dev/ntape/tape0_d0 /usr
# dump -0uf /dev/ntape/tape0_d0 /projects

This example may require additional media management to cross-reference dump files with tapes, especially when a single dump file spans media. Exercise care when labeling this type of backup media.

9.6.2    Performing an Incremental Backup

Set up a routine as part of your backup schedule to make it easier to remember which backup to do each day. Include a mechanism for logging your backups and their dump level and for listing the tapes on which they are made. Because of the chance of system corruption, do not keep this information on the local computer system.

After you establish a system for making incremental backups, the procedure is simple. Assume you use the following backup schedule to do a daily backup of /usr: 

0 1 9 9 9 1 9 9 9 9 ...
 

On Monday, perform a level 0 dump: 

# dump -0u /usr

On Tuesday, perform a level 1 dump: 

# dump -1u /usr

The level 1 dump backs up all the files that changed since Monday. On Wednesday through Friday, perform a level 9 dump (which always backs up all the files that have changed since Tuesday's level 1 dump): 

# dump -9u /usr

To perform the same level 9 dump to the tape device named /dev/tape/tape1_d0 instead of the default tape device, use the -f option as shown in the following example: 

# dump -9uf /dev/tape/tape1_d0 /usr

The argument to the -f option specifies a tape device local to the system from which you are performing the dumps.

9.6.3    Performing a Remote Backup

Some machines in a networked system environment may lack a local tape drive that you can use for making backup tapes. You can use the rdump command to make backups on a remotely located tape device. The rdump command is identical to the dump command except that it requires the -f option to specify the machine name and an attached backup device. See dump(8) for a description of the options to the rdump command.

The rdump command updates the /etc/dumpdates file on the local machine in the same way as does the dump command. The rdump command starts a remote server, /usr/sbin/rmt, on the remote machine to access the storage medium. This server process is transparent. See rmt(8) for more information.

To back up the /projects file system from bhost1 onto a tape drive on bhost2 with the attached backup device /dev/rmt0h, enter the following command from bhost1. The name of bhost1 must be defined in the /.rhosts file of bhost2 to allow access. 

# rdump -0uf bhost2:/dev/tape/tape0_d0 /projects

9.6.4    Using Backup Scripts

You can automate the backup process by using shell scripts. The cron daemon can execute these shell scripts late in the evening when there is less chance of the dump commands making errors from a changing system.

Backup shell scripts often perform the following tasks:

Some time during the day, load a tape into the tape drive. At the specified time, the cron daemon runs the backup shell scripts. After the shell procedures are finished, remove the backup tape and archive it.

Backup shell scripts are best used when the dump is small enough to fit on a single tape. You must specify the no-rewind device and the -N option to the dump command to inhibit the tape from going off line automatically when each dump is completed. After the dump command reaches the end of the tape, it takes the tape off line and you must replace the tape.

9.7    Restoring Data

Occasionally, you need to retrieve files from your backup tapes, and possibly need to restore entire file systems at some time. If you have set up a good backup procedure, then restoring files or full file systems is a simple task.

If a serious problem occurs, you may have to restore your entire system. Before restoring, determine what caused the problem with the system.

After determining the cause of the problem, reinstall your system from the initial boot tapes. The installation instructions that came with your system explain this procedure.

After your system is up and running, restore the system to the state it was in just prior to the system crash. If you are using AdvFS, use the vrestore command. See the AdvFS Administration manual for information on restoring the AdvFS file system. If you used the vdump command to back up a UFS file system, you can use the vrestore command to recover it. However, if you used the dump command you must use the restore command to recover files. Because the dump command saves only a single file system at a time, you must execute the restore command for each file system you want to restore. See restore(8) for information on the command syntax.

9.7.1    Restoring a File System

A general procedure for restoring a file system, such as after a disk failure or other loss of data, is described here. To restore individual files, go to Section 9.7.2.

To restore a file system, create a new file system and restore the files from the dump files by using the following commands:

newfs

Creates a new UFS file system. See newfs(8) for more information.

mount

Mounts the file system, making it available for general use. See mount(8) for more information.

cd

Changes your current working directory. See cd(1) for more information.

restore

Restores archived files from a backup media to a disk. See restore(8) for more information.

See the AdvFS Administration manual for information on restoring an AdvFS file system.

If the disk does not have a label, write the label by using the disklabel command before you create the new file system. See disklabel(8) for more information.

Writing a label with customized partition table settings may affect the entire disk. Use the following command to write the default disk partition table: 

# /sbin/disklabel -rw dsk1
 

Invoke the editing option of the disklabel command to use the customized partition table settings. See Chapter 6 for more information. You can use the Disk Configuration interface. See diskconfig(8) for more information.

The following example shows the commands you use to restore a file system called /usr/projects from a tape: 

# disklabel -rw dsk1
# newfs /dev/rdisk/dsk1c
# mount /dev/rdisk/dsk1c /usr/projects
# cd /usr/projects
# restore -Yrf /dev/tape/tape0_d0

9.7.2    Restoring Files Manually

If users lose data files, they ask their system administrator to restore those files. Users also may ask you to restore an earlier version of a file. Whatever the reason for a file restoration, you must determine which tape contains the correct version of the file. Inquire when the file was lost and when it was last modified, you can use your backup log to determine which tape contains the most recent version of the wanted file.

Use the -t option with the restore command to determine whether a file is on the selected tape. The -t option creates a list of files and directories on the tape. For example, to list the contents of the working subdirectory of the /usr file system on a particular backup tape, load the tape and enter: 

# restore -t ./working

To create a list of the entire contents of a backup tape, load the backup tape and enter: 

# restore -t

Make a listing of each backup tape after you create it. This verifies a successful backup and gives you a place to look up what files are on the tape.

After determining the location of the file, create a new directory for the file. If you restore the file into an existing directory and the file already exists, the restored file overwrites the existing file.

For example, to restore the working/old.file file from a /usr file system backup tape into your current directory, load the backup tape and enter: 

# restore -x ./working/old.file

To restore the entire contents of the working subdirectory from the same tape, enter: 

# restore -x ./working

If your dump media contains multiple dump images, you need to know the sequence of the dump images in order to restore a file from one of the images. To examine the contents of the first dump image on the media, load the tape and enter: 

# restore -ts 1

The -s option followed by the number 1 specifies the first dump image.

For example, to restore the working/old.file file from a /usr file system, which is the third dump image on the backup tape into your current directory, load the backup tape and enter: 

# restore -xs 3 ./working/old.file

9.7.3    Restoring Files Interactively

To ease the task of restoring multiple files, use the -i option to the restore command. This option starts an interactive restore session. The interactive mode has commands similar to shell commands.

To begin an interactive restore session, enter: 

# restore -i

The system responds with the following prompt: 

restore >
 

The following command line options are available in the interactive restore mode:

ls [ directory ]

Lists files in the current or specified directory. Directory entries end with a slash (/). Entries that are marked for reading begin with an asterisk (*).

cd [ directory ]

Changes the current directory to the directory specified by the directory argument.

pwd

Lists the pathname of the current directory.

add [ files ]

Adds the files in the current directory or the files specified by the files argument to the list of files recovered from the tape. Files are marked with an asterisk (*) if they are identified as "to be read" by the add command. You see this asterisk when you use the ls command to list files.

delete [ files ]

Deletes all the files in the current directory or the files specified by the files argument from the list of files recovered from the tape.

extract

Restores from the tape the files that are marked "to be read" into the current working directory. The extract command prompts you for the logical volume that you want to mount (usually 1), and whether the access modes of the dot (.) current directory are affected; answer yes when you are restoring the entire root directory.

setmodes

Sets owner, access modes, and file creation times for all directories added to the files-to-read list; no files are recovered from the tape. Use this command to clean up files after a restore command is prematurely aborted.

verbose

Toggles verbose mode. In verbose mode, each file name is printed to the standard output. By default, verbose mode is set to off. This is the same as the -v command line option to the restore command.

help

Lists a summary of the interactive commands.

?

Lists a summary of the interactive commands.

what

Lists the tape header information.

quit

Quits the interactive restore session.

xit

Exits from the interactive restore session. The xit command is the same as the quit command.

To interactively restore the ./working/file1 and ./working/file2 files from a backup tape, load the tape and enter: 

# restore -i

After you switch to interactive mode, follow these steps to add the files to the list of files that you want to extract:

  1. Change to the working directory: 

    restore > cd working

  2. Enter the file name at the prompt: 

    restore > add file1

  3. Enter the name of the second file as follows: 

    restore > add file2

  4. Extract the files as follows: 

    restore > extract

  5. You are prompted for the logical volume you want to mount; usually you respond to this prompt with 1 as shown in the following example: 

    You have not read any tapes yet.
Unless you know which volume your file(s) are on you can start
with the last volume and work towards the first.
 
Specify next volume #: 1

    You are then asked whether the extract affects the access modes of the dot (.) current directory. For this example, reply with n. 

    set owner/mode for '.'? [yn] n

  6. Quit the interactive session after the files are extracted: 

    restore > quit

The file1 and file2 files are now in the current directory.

You can automate this procedure in a command file that is read by the -F option to the restore command. For example, the following command file, named restore_file, performs the restore operation shown in the previous example: 

cd working
add file1
add file2
extract
1
n
quit

To read and execute this shell script, enter the following command: 

# restore -iF restore_file

The result of the procedure in this script is identical to that of the previous interactive restore session.

9.7.4    Restoring Files Remotely

You use the rrestore command to restore files to local directories from a remote tape device. The rrestore command requires the -f option to specify the machine name and its backup device. See rmt(8) for more information and Section 9.7 for a description of the options to the rrestore command.

You must specify the name of the remote system where the backup device is attached, and the name of the backup device on that remote system in the format system:device.

To restore the ./working/file1 file onto the local directory on system1 from a backup tape mounted on system2 where the backup device /dev/rmt0h is attached, enter the following command from system1. The name system1 must be in the /.rhosts file of system2 to allow access from system1 to system2. 

# rrestore -xf system2:/dev/tape/tape0_d0 ./working/file1

The rrestore command starts a remote server, /usr/sbin/rmt, on the remote system to access the storage medium.

9.7.5    Restoring or Duplicating a System (Root) Disk

In previous versions of the operating system, device names were assigned based on the physical location of the drive, according to the SCSI bus target. In Version 5.0 and higher, device names are assigned logically and stored in a database. They have no relationship to the bus address of the device. The device database must be recovered and possibly updated to successfully restore the root file system or if you want to move the root disk to a disk with larger capacity. Also, you may need to install devices (such as a tape device) to the device database when you restore the device from tape backup media.

After you reboot the system during the restoration, you may see the following message: 

Unable to save existing hardware configuration.
New configuration will be used

This message indicates that the device database is not recoverable and you must restore it.

The following procedure is a generic method for recovering or duplicating (cloning) a root disk. It covers the following possible scenarios:

Note

This procedure does not specifically address recovery methods from network backups and it does not address recovery of an AdvFS file system. See AdvFS Administration for more information.

Depending on your knowledge of your system, you may not need to read all the following sections:

9.7.5.1    Preparing for Recovery or Duplication

Depending on how your system is set up, and your level of system knowledge, you may need the following:

The status of your system must be as described in Table 9-1:

Table 9-1:  Recovery Preparation

Requirement Description
A Full and Recent Backup You need a full backup of all operating system file sets that are on the root volume. This may include root (/), /usr, and /var.
System Configuration

This procedure applies to all configurations where there is a single disk drive used for the root partition, which may contain the /usr and /var file systems. You need a functional disk drive to contain the restored root volume. This disk must have a minimum storage space as defined in the operating system limits for the restored release. The restore device (typically a tape drive) must be local and not a remote backup device.
Logical Storage Manager

If you are using the Logical Storage manager (LSM), see the Logical Storage Manager manual for information on recovering the root volume.
User Interface

This procedure requires a console login.

Affect on System Availability

Except on clustered systems, loss of the root disk invariably involves one or more shutdowns and reboots of the system. This procedure is intended to help you restore full operation as quickly as possible.

The time required for duplicating or recovering a disk depends on the disk size.
Privileges You must be a root user with physical access to the system's storage array and backup devices

9.7.5.2    Determining the Restoration Requirements

You may need the following resources to complete the restoration of your root disk. If you are very familiar with your system's configuration, or if you have a recovery plan which records all the information you need to perform a recovery, you do not need to read this section. You may need the following items:

9.7.5.3    Applying the Procedure

Some steps in the procedure are dependent on your system's original configuration. Ignore these steps if they do not apply to your configuration. The optional steps are marked [Configuration Dependent].

In the procedure, you always proceed to the next step unless redirected.

  1. Boot the system from the operating system distribution media by using one of the following methods:

  2. [Configuration Dependent] If you are already using the character-cell installation procedure, go to step 3, otherwise complete the following task.

    If your system has a graphics console, the installation defaults to graphical mode. Wait until the installation procedure displays a dialog box titled Installation Welcome.

    Pull down the File menu and select Exit to invoke character-cell mode.

  3. Verify the status of the backup device and the target disk (the restored root disk) by using the following command: 

    # hwmgr view devices

    The hwmgr command displays a list of all devices currently recognized by the system as shown in the following example: 

    HWID: Device Name         Mfg      Model            Location
 ------------------------------------------------------------------------
    4: /dev/kevm
   28: /dev/disk/floppy0c          3.5in floppy      fdi0-unit-0
   31: /dev/disk/dsk0c    DEC      RZ26L    (C) DEC  bus-0-targ-0-lun-0
   32: /dev/disk/dsk1c    DEC      RZ26     (C) DEC  bus-0-targ-1-lun-0
   33: /dev/disk/dsk2c    COMPAQ   HB00931B93        bus-0-targ-3-lun-0
   34: /dev/disk/cdrom0c  DEC      RRD45    (C) DEC  bus-0-targ-4-lun-0
   35: /dev/disk/dsk3c    COMPAQ   HB00931B93        bus-0-targ-5-lun-0
   37:                    DEC      TLZ06    (C)DEC   bus-0-targ-6-lun-0

    Locate and write down the following data:

  4. Install the backup device by using the following command: 

    # dn_setup -install_tape

    To verify the installation and determine the device name (such as tape0_d0), repeat the hwmgr command in step 3.

  5. [Configuration Dependent] If the original file system format is unknown, you can now ascertain it and verify that you have a readable backup tape as follows:

    1. Load the backup (dump) media into the device.

    2. Invoke the interactive mode of the restore command, specifying the backup device name that you determined in step 4. For example: 

      # restore -i -f /dev/ntape/tape0_d0

    3. If the backup is good, a prompt for interactive restoration is displayed. Enter the what command to display the header and record the information.

  6. Create and apply a disk label by using the following information:

    1. The partition plan that you created during recovery planning, including any swap space requirements. (See Section 9.7.5.2.)

    2. The new root device name determined in step 3.

    Specify the a partition and label the drive as a bootable device. For example: 

    # disklabel -wr /dev/disk/dsk2a

  7. Create your UFS target file systems as follows:

    You must create file systems on the new root drive for each file system that you need to restore. For example, to create the new root and /usr file systems on partitions a and g, use commands similar to the following: 

    # newfs /dev/disk/dsk2a
# newfs /dev/disk/dsk2g

  8. Mount the replacement disk on the temporary mount point /mnt according to the type of file system. For example: 

    # mount /dev/disk/dsk2a /mnt

  9. Use the vrestore or restore command to restore files. For example: 

    # cd /mnt
# vrestore -x device

  10. Shut down and halt the system by using the following command: 

    # shutdown -h now

  11. Boot the system to single-user mode, specifying the restored root drive as the boot device. For example: 

    >>> boot dka2 -flags s

    If you are using an alternate drive, or if you installed a new drive, you may need to translate the system device name to the appropriate boot device name. In step 3, you used the hwmgr command to determine the device database entry for the new device. For example: 

    33: /dev/disk/dsk2c COMPAQ HB00931B93 bus-0-targ-3-lun-0

    Use the following command to display the devices: 

    >>> show device

    Map the value of the b/t/l (in this case 0.3.0) to the alternate or new device and identify its boot device name, such as dka300.

  12. If the boot is successful, run the following script to update the device database: 

    # /sbin/mountroot

    While the dsfmgr command attempts to update the device database, some error or warning messages may be displayed. You can ignore the messages.

  13. [Configuration Dependent] If you installed a new drive for root, or you specified an alternate device, you need to rename devices. Using the device name information that you determined in step 3, rename the devices as follows:

  14. Using the interactive mode of the vrestore command, load the backup media into the restore device and restore the device directories. This step ensures that all appropriate devices, including any custom device drivers are recreated: