Installation Guide

Chapter 6. Creating System Backups

This chapter describes how to create and verify a bootable backup copy, or mksysb image, of your root volume group and how to make separate backup copies of user volume groups. References to CD in this chapter also apply to DVD.

Introduction

The root volume group is a hard disk or group of disks that contains:

• Startup files
• Operating system BOS
• System configuration information
• Optional software products

A user volume group, also called the nonroot volume group, typically contains data files and application software.

A system backup does the following:

• Contains a working copy of your system. In the event your system data becomes corrupted, you can use this information to restore your system to working order.
• Allows you to transfer installed and configured software from one system to others. You can use the Web-based System Manager or SMIT to make a backup image of the root volume group or user volume groups.

A backup transfers the following configurations from the source system to the target system:

• rootvg volume group information
• Paging space information
• Logical volume information
• Placement of logical partitions (if creating map files has been selected in the Web-based System Manager or SMIT).

  Note: The use of map files is not recommended if you plan to reinstall the backup to target systems other than the source system, or the disk configuration of the source system is to be changed before reinstalling the backup.

Using the Web-based System Manager or the SMIT backup menu lets you preserve configuration information, thus avoiding some of the configuring tasks normally required after restoring a system backup. A backup preserves the configuration if:

• The target system has the same hardware configuration as the source system.

  AND

• The target disk has enough space to hold the backup image.

The Web-based System Manager and SMIT both use the mksysb command to create a backup image, stored either on CD, on tape, or in a file. If you choose CD or tape, the backup program by default writes a boot image, which makes the medium suitable for installing. (For AIX 5.1, the Web-based System Manager interface does not support backups to DVD.) For more information, see Creating System Backups on CD-ROM.

Prerequisites for Creating Backups

Before creating system backups, complete the following prerequisites:

• Be sure you are logged in as root user.
• If you plan to use a backup image for installing other differently configured target systems, you must create the image before configuring the source system, or set the RECOVER_DEVICES variable to no in the bosinst.data file. Refer to Chapter 8, Customized BOS Installations for more information about the bosinst.data file.
• Consider altering passwords and network addresses if you use a backup to make master copies of a source system. Copying passwords from the source to a target system can create security problems. Also, if network addresses are copied to a target system, duplicate addresses can disrupt network communications.
• Mount all file systems you want to back up. The mksysb command only backs up mounted JFS (Journaled File Systems) in the rootvg. Refer to the mount command for details.

  Note: The mksysb command does not back up file systems mounted across an NFS network.

• Unmount any local directories that are mounted over another local directory.

  This backup procedure backs up files twice if a local directory is mounted over another local directory in the same file system. For example, if you mount /tmp over /usr/tmp, the files in the /tmp directory are then backed up twice. This duplication might exceed the number of files a file system can hold, which can cause a future installation of the backup image to fail.

• Use the /etc/exclude.rootvg file to list files you do not want backed up.

• Make at least 8.8 MB of free disk space available in the /tmp directory. The mksysb command requires this working space for the duration of the backup.

  Use the df command, which reports in units of 512-byte blocks, to determine the free space in the /tmp directory. Use the chfs command to change the size of the file system, if necessary.

  For example, the following command adds 12 MB of disk space to the /tmp directory of a system with 4 MB partitions:

  chfs -a size=+24000 /tmp
  

• All hardware must already be installed, including external devices, such as tape and CD-ROM drives.
• The bos.sysmgt.sysbr fileset in the BOS System Management Tools and Applications software package must be installed. The bos.sysmgt.sysbr fileset is automatically installed in AIX 5.1. Enter the following command to determine if the bos.sysmgt.sysbr fileset is installed on your system:

  lslpp -l bos.sysmgt.sysbr
  

  If your system has the bos.sysmgt.sysbr fileset installed, continue with either Creating a Root Volume Group Backup to Tape or File or Creating a User Volume Group Backup.

  If the lslpp command does not list the bos.sysmgt.sysbr fileset, install it before continuing with the backup procedure. Refer to Chapter 4, Optional Software Products and Service Updates for instructions, or enter the following command:

  installp -agqXd device bos.sysmgt.sysbr
  

  where device is the location of the software; for example, /dev/cd0 for CD-ROM drive.

Creating a Root Volume Group Backup to Tape or File

You can use either the Web-based System Manager or SMIT to create a system backup. These backups can be stored to CD, DVD, tape, or in a file. Booting from tape is not supported on Itanium-based platforms.

CD/DVD instructions are slightly different. See Creating System Backups on CD-ROM.

To create a root volume group backup:

• Use the Web-based System Manager Backup and Restore application and select Back up the system.

  OR

• Use the following SMIT procedure:
  1. Enter the smit mksysb fast path.
  2. In the Back Up the System menu, make the following selections:
     • Select which medium you want to use in the Backup DEVICE or File field. If you want to create a bootable backup, the medium must be tape or CD. See Creating System Backups on CD-ROM for more information. Then, follow the appropriate step below:

       TAPE

       Press the F4 key to list available devices and highlight the device name.

       FILE

       Enter a full path and file name in the entry field.

     • If you want to create map files, select yes in the Create Map Files? field.

       Map files match the physical partitions on a drive to its logical partitions. When installing from a backup image, the BOS installation program uses map files to position the logical volumes on the target drive in the same partitions they were on in the source system. If you do not create map files, the installation program relies on the logical volume manager (LVM) to determine placement for the logical volumes. For more information, see Using Map Files for Precise Allocation in AIX 5L Version 5.1 System Management Concepts: Operating System and Devices.

       Note: If you plan to reinstall the backup to target systems other than the source system, or if the disk configuration of the source system might change before reinstalling the backup, do not create map files.

     • To exclude certain files from the backup, select yes in the Exclude Files field, then create an /etc/exclude.rootvg file with an ASCII editor, and enter the file names that you do not want included in your system backup image. You can use patterns for the file names that conform to the pattern matching conventions of the grep command. For example, to exclude all the contents of the directory called scratch, put the following line in the exclude file:

       /scratch/
       

       For another example, exclude the contents of the directory called /tmp and avoid excluding any other directories that have /tmp in the pathname by adding the following line to the exclude file:

       ^./tmp/
       

       Note: All files are backed up relative to the current working directory. This directory is represented by a . (dot character). To exclude any file or directory for which it is important to have the search match the string at the beginning of the line, use a ^ (caret character) as the first character in the search string, followed by a . (dot character), and then followed by the filename or directory to be excluded.

       If the filename or directory being excluded is a substring of another filename or directory, use ^. (caret character followed by dot character) to indicate that the search should begin at the beginning of the line and/or use $ (dollar sign character) to indicate that the search should end at the end of the line.

     • To list each file as it is backed up, select yes in the List files as they are backed up? field. Otherwise, you see a percentage-completed progress message while the backup is created.
     • If you modified the image.data file and do not want a new one created, select no for Generate new /image.data file?. (The image.data file contains information about the sizes of all the file systems and logical volumes in your rootvg.)
     • If you are creating a bootable tape and you want to expand the system /tmp file system (if required by the backup program), select yes for EXPAND /tmp if needed?.
     • If the tape drive you are using provides packing (or compression), set the Disable software packing of backup? field to yes.
     • If you chose tape as the backup medium, either leave the default in the Number of BLOCKS to write in a single output field or enter a different number.
     • If you chose file as the backup medium, press Enter. If you chose tape as the backup medium, insert the first blank backup tape into the drive and press Enter.
  3. The COMMAND STATUS screen displays, showing status messages while the system makes the backup image.

     If you chose tape as the backup medium, the system might prompt you to insert the next tape during the backup by displaying a message similar to the following:

     Mount next Volume on /dev/rmt0 and press Enter.
     

     If this message displays, remove the tape and label it, including the BOS version number. Then insert another tape and press Enter.

     When the backup process finishes, the COMMAND: field changes to OK.

  4. Press F10 to exit SMIT when the backup completes.
  5. If you chose tape as the backup medium, remove the last tape and label it. Write-protect the backup tapes.
  6. Record any backed-up root and user passwords. Remember that these passwords become active if you use the backup to either restore this system or install another system.

You have created the backup of your root volume group (rootvg). If you created bootable tapes, you can use these tapes to start your system if for some reason you cannot boot from hard disks.

Creating System Backups on CD-ROM

Creating a backup CD/DVD is similar to making a backup tape for your personal use, but with some noticeable differences.

Note: For information about CD/DVD-R/DVD-RAM drives and CD/DVD-R creation software, refer to the following README file:

/usr/lpp/bos.sysmgt/mkcd.README.txt

The Web-based System Manager and SMIT both use the mkcd command, which calls the mksysb or savevg command, if needed. For system backups, the CDs can be created as:

• Non-bootable CDs
• Generic CDs (bootable on any target system)
• Personal CDs (bootable only on the source system)

Notes:

• Only CHRP systems support booting from DVD.
• Web-based System Manager does not support backups to DVD.
• POWER-based platform backups and Itanium-based platform backups are not interchangeable. For example, generic CD produced on a POWER-based platform cannot be used to install or recover an Itanium-based platform.

Personal and Generic backup CDs

There are two types of backup CDs that can be created. The first is called a personal backup CD, which is similar to a backup tape. A personal backup CD can only boot and install the machine on which it was created.

The second type of CD is a generic backup CD. A generic backup CD created on one POWER-based machine can boot any other POWER-based machine. It contains three boot images and all the device and kernel packages necessary to install any system. The mksysb image that is stored on the CD does not require that all the devices be installed in it, because the installation process installs the needed devices for that machine from the packages on the CD. A generic backup CD can be used to install (clone) a large number of machines in a customer's environment, which is particularly convenient when each machine in the system environment needs to have the same image installed, but all machines might not have the same hardware configuration.

Web-based System Manager and SMIT interfaces are available for the mkcd command. Online help can guide you through the required steps.

Another option available with the mkcd command is the ability to create a savevg CD. This CD has a copy of a non-rootvg volume group on it, and is useful for volume groups that contain user data. The mkcd command currently supports saving one volume group at a time to a CD. A new -L flag allows the creation of DVD sized images. However, if your rootvg image and savevg image are small enough to fit on one CD, you can save them both by taking advantage of the -l (stacklist) and -z (customization_script) flags. The -l flag gives a list of images to copy to the CD. The -z flag lets you create a script to restore savevg backups. For example, if you make a copy of a non-rootvg volume group ahead of time, and then write a script that calls the restvg command, then your non-rootvg would be restored to hdisk2 at the end of the installation of rootvg, as shown by the following command:

restvg -d /SPOT/usr/sys/inst.images/savevg_image hdisk2

This procedure is recommended only if you know you want to restore the non-rootvg volume group every time you install. Otherwise, you might just want to store it on the CD/DVD, then use restvg to restore it after reboot. The restvg command can restore from CD if the name of the image is savevg_image. If you save the non-rootvg backup on a CD with a different filename, you can insert that CD and use the full path to the filename as the device for the restvg command.

Hardware and Software Requirements

You must obtain the hardware and software necessary to create a CD/DVD. The command for this process, mkcd, requires that you already have the software to create a CD or DVD-ROM file system in Rock Ridge format and to burn or write the CD. Hardware and software that has been tested with this command includes:

Note: For more information about CD/DVD-R/DVD-RAM drives and CD/DVD-R creation software, refer to the following README file:

/usr/lpp/bos.sysmgt/mkcd.README.txt

Using the mkcd Command

Note: For information on using the mkcd command with Itanium-based platforms, refer to the following README file:

/usr/lpp/bos.sysmgt/mkcd.README.txt

To run the mkcd command, you need extra working space. A separate file system or directory is required for each of the following:

• Storing a mksysb or savevg image
• Storing the CD/DVD file system contents
• Storing the CD/DVD images before they are recorded

The mkcd command creates the following file systems if they are not already present or if alternative file systems or directories have not been specified:
/mkcd/mksysb_images
/mkcd/cd_fs
/mkcd/cd_images

The space used in these file systems is only temporary (unless the -R or -S flag is specified to save the images). If the mkcd command creates the file systems, it also removes them. Each file system or directory might require over 645 megabytes (up to 4.38 GB for DVD). The /mkcd/cd_fs directory needs 645 megabytes (up to 4.38 GB for DVD). The /mkcd/mksysb_images directory's space requirement depends on the size of the mksysb image that is to be created. The mkcd process attempts to calculate this space and verify that adequate space is available before starting the mksysb image. The /mkcd/cd_image directory needs at least 645 megabytes (up to 4.38 GB for DVD) of space. If the -R or -S flags are used to specify not removing the images and there are multiple volumes required, then more space must be provided.

If you do not have space on your machine, you might want to use NFS to mount some space from another server system, however, the file systems must be writeable. You can create a /mkcd file system that is very large (1.5 gig for CD or 9 GB for DVDs) and then create subdirectories for cd_fs, mksysb_images, and cd_images under /mkcd. Then /mkcd can be mounted onto the clients when they want to create a backup CD/DVD for their systems. When creating very large backups (larger than 2 GB) for DVD with the mkcd command, the file system must be large-file enabled and the ulimit values must be set to unlimited.

Creating a Root Volume Group Backup on CD/DVD-ROM

To create a root volume group backup:

• Use the Web-based System Manager Backup and Restore application and select System backup to writable CD. This method lets you create generic or personal system backups on CD-ROM media.

  OR

• Use the following SMIT procedure:
  1. Enter the smit mkcd command. The system asks whether you are using an existing mksysb image.
  2. Enter the name of the CD-R device. (This can be left blank if Create the CD now? field is set to no.)
  3. If you are creating a mksysb image, you must select the image-creation options. The options are as follows:
     • Create map files?
     • Exclude files?

     Refer to steps 3 and 4 of Creating a Generic Backup CD/DVD Using SMIT . The mkcd command always calls the mksysb command with the flags to extend /tmp, to create an image.data file, and to use software packing for the backup.

  4. Enter the file system/directory in which to store the mksysb image. This can be a file system you created in the rootvg, in another volume group, or in NFS mounted file systems. If left blank, the mkcd command creates the file system and removes it when the command completes.
  5. In the next two fields, you can enter the file systems and directories where the CD/DVD file system and CD/DVD images are to be stored. These can be file systems you created in the rootvg, in another volume group, or in NFS mounted file systems. If these fields are left blank, the mkcd command creates these file systems, and removes them when the command completes, unless you specify differently in later steps in this procedure.
  6. If you did not enter any information in the file systems' fields, you can select to have the mkcd command either create these file systems in the rootvg, or in another volume group. If the default of rootvg is chosen and a mksysb image is being created, the mkcd command adds the file systems to the exclude file and calls the mksysb command with the exclude files option -e.
  7. Do you want the CD/DVD to be bootable? If you select yes, this CD is written to be bootable only on the source system on which it was created. If you select no, you must boot from a product CD at the same version/release/maintenance level, and then select to install the system backup from the system backup CD.
  8. If you change the Remove final images after creating CD? field to no, then the file system for the CD images (that you specified earlier in this procedure) remains after the CD has been recorded.
  9. If you change the Create the CD now? field to no, then the file system for the CD images (that you specified earlier in this procedure) remains. The settings you selected in this procedure remain valid, but the CD is not created at this time.
  10. If you intend to use an Install bundle file, enter the full path name to the bundle file. The mkcd command copies the file into the CD file system. You must have the bundle file already specified in the BUNDLES field, either in the bosinst.data file of the mksysb image or in a user-specified bosinst.data file. When this option is used to have the bundle file placed on the CD, then the location in the BUNDLES field of the bosinst.data file must be as follows:

      /../usr/sys/inst.data/user_bundles/bundle_file_name
      

  11. Additional packages can be placed on the CD by entering the name of the file that contains the packages list in the File with list of packages to copy to CD field. The format of this file should be one package name per line.

      If you are planning to install one or more bundles after the mksysb image is restored, follow the directions in the previous step to specify the bundle file. Then you can use this option to have packages listed in the bundle available on the CD. If this option is used, you must also specify the location of installation images in the next step.

  12. Enter the location of installation images that are to be copied to the CD file system (if any) in the Location of packages to copy to CD field. This field is required if additional packages are to be placed on the CD (see the previous step). The location can be a directory or CD device.
  13. You can specify the full path name to a customization script in the Customization script field. If given, the mkcd command copies the script to the CD file system. You must have the CUSTOMIZATION_FILE field already set in the bosinst.data file in the mksysb image or else use a user-specified bosinst.data file with the CUSTOMIZATION_FILE field set. The mkcd command copies this file to the RAM file system. Therefore, the path in the CUSTOMIZATION_FILE field must be as follows:

      /../filename
      

  14. You can use your own bosinst.data file, rather than the one in the mksysb image, by entering the full path name of your bosinst.data file in the User supplied bosinst.data file field.
  15. To turn on debugging for the mkcd command, set Debug output? to yes. The debug output goes to the smit.log.
  16. You can use your own image.data file, rather than the image.data file in the mksysb image, by entering the full path name of your image.data file for the User supplied image.data file field.

Creating a Generic Backup CD/DVD Using SMIT

To use SMIT for creating a generic backup CD/DVD, follow these steps:

1. Enter the smit mkcdgeneric command.
2. Enter the name of the CD-R device. This can be left blank if the Create the CD now? field is set to no.
3. Enter the full path name of the mksysb image. You can use only previously created mksysb images. This path does not create a mksysb image for you.
4. Enter the location of the installation images that are to be copied to the CD file system in the Location of packages to copy to CD field. This field is required to copy devices and kernel packages to the generic CD. Additional software packages can be copied onto the generic CD, if a list of packages is provided in a later step of this procedure. The location can be either a directory or a CD device.
5. In the next two fields, enter the file systems and directories where the CD file system and CD images are to be stored. These can be file systems you created in the rootvg, in another volume group, or in NFS-mounted file systems. If these fields are left blank, the mkcd command creates these file systems, and removes them when the command completes, unless you specify differently in later steps in this procedure.
6. If you left the file systems' fields blank, you can select to have the mkcd command either create these file systems in the rootvg, or in another volume group.
7. If you change the Remove final images after creating CD? field to no, then the file system for the CD images (that you specified earlier in this procedure) remains after the CD has been recorded.
8. If you change the Create the CD now? field to no, then the file system for the CD images (that you specified earlier in this procedure) remains. The settings you selected in this procedure remain valid, but the CD is not created at this time.
9. If you intend to use an Install bundle file, enter the full path name to the bundle file. The mkcd command copies the file into the CD file system. You must have the bundle file already specified in one of the following: the bosinst.data file, the BUNDLES field in the mksysb image, or a user-specified bosinst.data file that has the BUNDLES field set appropriately. When this option is used to have the bundle file placed on the CD, then the location in the BUNDLES field of the bosinst.data file must be as follows:

   /../usr/sys/inst.data/user_bundles/bundle_file_name
   

10. Additional packages can be placed on the CD by entering the name of the file that contains the packages list in the File with list of packages to copy to CD field. The format of this file should be one package name per line.

    If you are planning to install one or more bundles after the mksysb image is restored, follow the directions in the previous step to specify the bundle file. Then you can use this option to have packages listed in the bundle available on the CD. If this option is used, you must also specify the location of installation images in the next step.

11. You can specify the full path name to a customization script in the Customization script field. If given, the mkcd command copies the script to the CD file system. You must have the CUSTOMIZATION_FILE field already set in the bosinst.data file in the mksysb image or else use a user-specified bosinst.data file with the CUSTOMIZATION_FILE field set. The mkcd command copies this file to the RAM file system. Therefore, the path in the CUSTOMIZATION_FILE field must be:

    /../filename
    

12. You can use your own bosinst.data file, rather than the one in the mksysb image, by entering the full path name of your bosinst.data file in the User supplied bosinst.data file field.
13. To turn on debugging for the mkcd command, set Debug output? to yes. The debug output goes to the smit.log.
14. You can use your own image.data file, rather than the image.data file in the mksysb image, by entering the full path name of your image.data file for the User supplied image.data file field.

Creating a User Volume Group Backup

Use either Web-based System Manager or SMIT to back up user volume groups. In AIX 4.3.3 and later versions, you can back up a user volume group to CD.

Creating a User Volume Group Backup Using Web-based System Manager

Use Web-based System Manager and select System backup to writable CD. This method creates a non-bootable CD that contains only a volume group backup image of a user volume group.

Creating a User Volume Group Backup Using SMIT

To back up a user volume group to tape or file using SMIT, type smit savevg on the command line. Back up a user volume group to CD by typing smit savevgcd on the command line.

When the Save a Volume Group screen displays, use the steps for backing up the root volume group as a guide for backing up user volume groups. There is one exception to this procedure. If you want to exclude files in a user volume group from the backup image, create a file named /etc/exclude.volume_group_name, where volume_group_name is the name of the volume group you want to backup.

Next, edit the /etc/exclude.volume_group_name file and enter the patterns of file names that you do not want included in your backup image. The patterns in this file are input to the pattern-matching conventions of the grep command to determine which files are excluded from the back up.

Verifying a System Backup

To list the contents of a mksysb image on tape or CD, you can use either Web-based System Manager (type wsm on the command line, then choose the Backup and Restore application) or SMIT (type smit lsmksysb on the command line). The listing verifies most of the information on the tape or CD, but does not verify that the backup media can be booted for installations. The only way to verify that the boot image(s) on a mksysb tape or CD function properly is by booting from the media. To verify all the boot images on a generic CD, try to boot from the CD on each different platform on which you are installing the backup.