Backing Up a Non-Root Volume Group in AIX 4.x

Contents

This document details the commands for creating, verifying, and restoring a volume group backup in AIX Versions 4.x. This document should only be used as a supplement to the AIX System Management Guide.

Since the mksysb command only backs up the root volume group, another approach is needed to back up other volume groups on the system. In these cases, the savevg command is used to create a backup of a volume group. The restvg command restores a savevg image, including recreating the volume group and its logical volumes and file systems.

WARNING: All logical volume information is archived and will be recreated. However, only JFS-mounted file system data will be archived. Raw logical volume data will NOT be archived using a savevg. For more information on raw logical volumes, contact your AIX support center.

Unlike the mksysb command, the savevg command cannot be used to create a bootable tape. It consists of only one image, whether it is written to a tape drive or to a file on the system. This image is in the backup and restore format.

• Using SMIT

  Fill in the correct device or file name to be used. Press Enter to start the backup. If the user is writing the savevg to tape and more than one tape is required, SMIT will prompt the change of the tape. Enter:

      smit savevg 
      Backup DEVICE or FILE                         [ ] 
      Create MAP files?                             no 
      EXCLUDE files?                                no 
      Number of BLOCKS to write in a single output  [ ] 
            (Leave blank to use a system default) 
  

  or

• From the command line, enter:

      savevg -if /dev/rmt# vgname 2>/tmp/savevg.err 
  

  NOTE: A savevg is not bootable when written to tape.

  WARNING: When you are creating a savevg to tape, do not stack the image onto an existing tape. A savevg image must be the first image on the tape to restore it.

The only method to verify that a volume group backup will correctly restore with no problems is to actually restore the savevg onto another machine. This should be done following the company's DISASTER RECOVERY PLAN.

To minimize problems due to tape media damage, perform the following test.

WARNING: This test only verifies that the tape media can be read on this machine and does NOT guarantee that the savevg will be restored successfully.

1. Using SMIT, enter:

       smit lsbackvg 
       DEVICE or FILE                               [/dev/rmt#] 
       Number of BLOCKS to read in a single input   [ ] 
           (Leave blank to use a system default) 
   

   Type or select values and press Enter only AFTER selecting all values.

2. Enter:

       restore -Tvqf /dev/rmt#.1 > /tmp/savevg.log 
   

• Using SMIT, enter:

      smit restvg 
      Restore DEVICE or FILE                       [/dev/rmt0] 
      SHRINK the filesystems?                       no 
      PHYSICAL VOLUME names                        [ ] 
         (Leave blank to use the PHYSICAL VOLUMES listed 
          in the vgname.data file in the backup image) 
      Number of BLOCKS to read in a single input   [ ] 
         (Leave blank to use a system default) 
  

  Be sure to select all physical volumes that will make up the new volume group.

• To restore from the command line, enter:

      restvg -f /dev/rmt# hdisk# {hdisk# ...} 
  

For example:

    restore -xvqf /dev/rmt# ./path/file_to_restore 

The savevg is always created with relative path names.

1. The restvg command expects the savevg image to be the first image on the tape. If the savevg image is not the first image on a tape, the restvg command is not supported as a means to restore that image. Individual files can still be restored from that image, but the tape must be forwarded to the correct filemark. For further information on the restore command, contact your AIX support center.

2. For savevg and restvg to work properly with an image that was created with both maps and mirroring, AIX must be at the proper maintenance level of bos.sysmgt.sysbr. To verify the level, enter:

       lslpp -h bos.sysmgt.sysbr 
   

   Use the following table to verify that AIX is at the correct fileset level:

    < 4.1.4         ** not supported ** 
    4.1.4           bos.sysmgt.sysbr 4.1.4.5 
    4.1.5           bos.sysmgt.sysbr 4.1.5.0 
    4.2.0           bos.sysmgt.sysbr 4.2.0.5 
    4.2.1           bos.sysmgt.sysbr 4.2.1.0 
    4.3.0           bos.sysmgt.sysbr 4.3.0.0