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Commands Reference, Volume 3
Creates an installable image of
the root volume group either in a file or onto a bootable tape.
mksysb [ -b
Number ] [ -e ] [ -p ] [ -v
] [ -X ] [ -i | -m ] Device |
File
The mksysb command
creates a backup of the operating system (that is, the root volume
group). You can use this backup to reinstall a system to its original
state after it has been corrupted. If you create the backup on tape,
the tape is bootable and includes the installation programs needed to install
from the backup.
The file-system image is in
backup-file format. The tape format includes a boot image, a bosinstall
image, and an empty table of contents followed by the system backup (root
volume group) image. The root volume group image is in backup-file
format, starting with the data files and then any optional map files.
One of the data files mksysb uses is the
/bosinst.data file. If a
/bosinst.data file doesn't exist,
/var/adm/ras/bosinst.data is copied to /
(root). In AIX 4.3.3 and later versions,
mksysb always updates the target_disk_data stanzas in
bosinst.data to match the disks currently in the root volume
group of the system where the mksysb command is running.
If you are using a customized /bosinst.data file and do
not want the target_disk_data stanzas updated, you must create the file
/save_bosinst.data_file. The mksysb
command does not update /bosinst.data if the
/save_bosinst.data_file exists.
Notes:
- The image the
mksysb command creates does not include data on raw devices or in
user-defined paging spaces.
- If you are using a
system with a remote-mounted /usr file system, you cannot reinstall
your system from a backup image.
- The mksysb
command may not restore all device configurations for special features, such
as /dev/netbios and some device drivers not shipped with the
product.
- Some rspc systems do
not support booting from tape. When you make a bootable mksysb image on
an rspc system that does not support booting from tape, the mksysb
command issues a warning indicating that the tape will not be bootable.
You can install a mksysb image from a system that does not support booting
from tape by booting from a CD and entering maintenance mode. In
maintenance mode you will be able to install the system backup from
tape.
To create a backup of the operating system to CD, please refer to the
mkcd command.
| -b Number
| Specifies the number of 512-byte blocks to write in a single output
operation. When the backup command writes to tape devices,
the default is 100 for backups by name.
The write size is the number of blocks multiplied by the block size.
The default write size for the backup command writing to tape
devices is 51200 (100 * 512) for backups by name. The write size must
be an even multiple of the tape's physical block size.
|
| -e
| Excludes files listed in the /etc/exclude.rootvg file
from being backed up. The rules for exclusion follow the pattern
matching rules of the grep command.
Note: If you want to exclude certain files from the backup,
create the /etc/exclude.rootvg file, with an ASCII editor,
and enter the patterns of file names that you do not want included in your
system backup image. The patterns in this file are input to the pattern
matching conventions of the grep command to determine which files
will be excluded from the backup. If you want to exclude files listed
in the /etc/exclude.rootvg file, select the Exclude Files
field and press the Tab key once to change the default value to yes.
For example, to exclude all the contents of the directory called scratch,
edit the exclude file to read as follows:
/scratch/
For example, to exclude the contents of the directory called
/tmp, and avoid excluding any other directories that have
/tmp in the pathname, edit the exclude file to read as
follows:
^./tmp/
All files are backed up relative to . (current working
directory). 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 ^ (caret
character) as the first character in the search string, followed by
. (dot character), 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.
|
| -i
| Calls the mkszfile command, which generates the
/image.data file. The /image.data
file contains information on volume groups, logical volumes, file systems,
paging space, and physical volumes. This information is included in the
backup for future use by the installation process.
Note: Before running the mkszfile command, ensure
that enough space is available in the /tmp file to store a boot
image. This space is needed during both backup and installation.
To determine the amount of space needed in the /tmp file, issue the
following command:
bosboot -q -a -d device
If you use the -X flag with the mksysb command, you
do not need to run the bosboot command to determine the amount of
space needed in the /tmp file.
|
| -m
| Calls the mkszfile command, with the -m flag to
generate map files.
|
| -p
| Disables software packing of the files as they are backed up. Some
tape drives use their own packing or compression algorithms. This flag
only applies to AIX 4.2 or later.
|
| -v
| Verbose mode. Lists files as they are backed up. This flag
only applies to AIX 4.2 or later.
|
| -X
| Specifies to automatically expand the /tmp file system if
necessary. The /tmp file system may need to be extended to
make room for the boot image when creating a bootable backup to tape.
This flag only applies to AIX 4.2 or later.
|
| Device |
File
| Specifies the name of the device or file.
|
- To generate a system
backup and create an /image.data file (generated by the
mkszfile command) to a tape device named /dev/rmt0,
enter:
mksysb -i /dev/rmt0
- To generate a system
backup and create an /image.data file with map files
(generated by the mkszfile command) to a tape device named
/dev/rmt1, enter:
mksysb -m /dev/rmt1
- To generate a system
backup with a new /image.data file, but exclude the files in
directory /home/user1/tmp, create the file
/etc/exclude.rootvg containing the line
/home/user1/tmp/, and enter:
mksysb -i -e /dev/rmt1
This command will backup the /home/user1/tmp directory but not
the files it contains.
- To generate a system
backup file named /mksysb_images/node1 and a new
/image.data file for that image, enter:
mksysb -i /userimage/node1
Note: This file will not be bootable and can only be
installed using Network Installation Management (NIM).
| /usr/bin/mksysb
| Contains the mksysb command.
|
The backup command, bosboot command, mkcd command, mkszfile command.
The /image.data file.
A procedure to verify the mksysb
backup can be found in the article "Verifying a System
Backup" in the AIX 5L Version 5.1 Installation
Guide.
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