ITEM: BX0549L
What is the difference between sysback ver 3 and sysback ver 4.1
Question:
590
customer wants the news version of sysback.
Response:
Customer Contact
Response:
ENV:
AIX 4.1.4
RISC 590
*CUSTOMER REP: Shannon Sylvia
PROBLEM:
Customer wanted to know the differences between version 3 and
version 4 of sysback
*ACTION TAKEN:
===========================================
AIX System Backup & Recovery/6000 (Sysback)
Version 4.1 Release Notes
===========================================
The purpose of this documente is to describe the differences between
Sysback Version 4.1 and Sysback Version 3.3. It is assumed that the
reader is already familiar with Sysback Version 3.3. The information
contained here will act as a suppliment to, or provide changes to,
the Sysback Version 3 User and Reference Manual.
AIX Support
-----------
Sysback Verison 4 may be installed only on AIX Version 4.1 and later
operating systems. Support for AIX Verison 3.2 is no longer provided
by this version of Sysback.
Backward Compatibility
----------------------
Sysback Version 4 is not compatible with Sysback Version 3. This
means:
1. Both client and server systems in a network backup environment must
be running the same version of Sysback.
2. With the new version of Sysback installed, it will NOT be possible
to restore data from Sysback backups created at prior versions.
3. To perform a System Installation from tape, you must boot from a
tape created with Sysback Version 4 if you are restoring from a backup
created with Sysback Version 4. You cannot boot from a Sysback Version
4 tape and install from a Sysback Version 3 backup, and vice-versa.
4. To perform a Sysback Network Install, you must boot from a server
running the same version of Sysback as was used to create the backup
you will be installing.
What you CAN do:
1. You may still boot and install from your Sysback Version 3 backup
tapes.
2. You may re-install the Sysback Version 3 software over Sysback Version
4 if it is necessary to restore from backups created with Sysback
Version 3. You may later re-install Sysback Version 4 without loss
of any customized configuration.
=============================
Changes to Existing Functions
=============================
Sysback SMIT Menus
------------------
The SMIT menus for Sysback Backup, List, Verify, Recreate and Restore
functions have been simplified. In prior versions, there was a separate
menu for each backup type (i.e. System, Volume Group, Filesystem,
etc), used to perform all backup, list, verify, recreate, and restore
options. The Sysback Main Menu now contains the following option:
Backup & Recovery Options
When selecting this option, the additional options will appear:
*********************************************************
Backup Options
List Backup Contents
Verify a Backup
Recreate Volume Groups, Logical Volumes & Filesystems
Restore Data from a Backup
*********************************************************
The "List", "Verify", "Recreate" and "Restore" options may be performed
on any type of backup performed with Sysback. It is no longer necessary
to know the backup type or select a different option for each backup
type. SMIT will determine the type of backup for you and display
only the subsequent options which apply.
By selecting "Backup Options" on this screen, you will be presented
with the following additional list of selections:
*********************************************************
Backup the System (Installation Image)
Backup Volume Groups
Backup Filesystems
Backup Logical Volumes
Backup Files or Directories
*********************************************************
From this screen, you must select the type of backup to be performed.
The options which follow will differ based on the type of backup
to be performed.
SMIT Device Selection Screen
----------------------------
When performing Sysback backups from SMIT, you will be given an option
of a Directory, indicated by the "Dir" prefix, to write the backups
to. This replaces the previous "File" option, which provided the
full pathname of a file into which the backup was written.
Now, a directory option is displayed for each directory for which
the user has permission to write backups (on both the local and remote
hosts). After selecting a directory, SMIT will automatically create
a default filename to create based on the selected directory, backup
type, hostname, and unique ID as follows:
/DirectoryPath/Type.hostname.ID
where Type is one of:
SB System Backup
VG Volume Group Backup
FS Filesystem Backup
LV Logical VOlume Backup
FD File or Directory Backup
and Unique ID is, by default, the date and time expressed as "MMDDhhmm".
The Unique ID field may be changed in the SMIT dialog screen which
follows. By using a unique ID, each backup will be written to a different
file. IB the same ID is used for different backups of the same type,
the former backup may be overwritten with the new backup.
For all list, verify, recreate, and restore options, you will continue
to be given the "File" option, displaying the directory and filename
created as described above.
System and Volume Group Backups
-------------------------------
There have been considerable change to the format of the System backup,
both when writing to tape or to disk files. In the past, the System
backup contained a separate image (on tape) for each volume group.
For disk image backups, a separate backup had to be performed for
the system (rootvg) and each additional volume group.
This new version of Sysback breaks each filesystem and logical volume
into separate images, both when writing to tape and to disk files.
This provides several enhancements:
1. Both filesystems and raw logical volumes will be included in the
System and Volume Group backups.
Because, previously, a volume group backup could contain only one
image, only the filesystem data could be included. Now that there
is a separate image for each filesystem, a separate image can be
as easily added for each raw logical volume.
2. System Backups to disk file may contain multiple volume groups.
The actual disk file backup that is created contains multiple files,
one for each logical volume or filesystem and one to contain a table
of contents for the backup.
3. A single Volume Group Backup may now be performed for multiple volume
groups.
If more than one volume group is specified, the filesystems and logical
volumes for all specified volume groups will be combined into a single
backup, and later list, verify, recreate or restore operations may
be performed separately or collectively for the volume groups included
on the backup.
4. Restoring of volume group data becomes more flexible.
Since each filesystem and logical volume is in a separate image,
it is now possible to exclude certain filesystems or logical volumes
from being restored. This is possible by selecting only specific
filesystems or logical volumes to restore to an existing volume group,
or by selecting not to create certain filesystems or logical volumes
during the Sysback System Installation process.
5. Faster restoration of specific filesystems, files or directories.
Since filesystems are separate images on a backup, it is not necessary
to "read through" all of the unnecessary filesystem data to reach
the data to be restored. For tape backups, the tape is "fast-forwarded"
past any irrelevant data. For disk file backups, only the actual
disk file or files containing the data to be restored need to be
read. This is a dramatic improvement over the previous need to read
through an entire volume group to find specific files to restore.
6. Better recovery from tape I/O errors
It is not possible to "read" past an I/O error produced by a tape
drive. However, it is possible to "skip" past any images containing
an I/O error to the start of the next image. This means, for instance,
that, when restoring from a volume group backup, an I/O error may
make the remainder of a filesystem unreadable, but the Sysback restore
process will skip to the beginning of the next filesystem (or raw
logical volume) and continue automatically. Obviously, an I/O error
continues to make backup data unreadable, but the amount of data
affected is severely limited.
Filesystem and Logical Volume Backups
-------------------------------------
A single Filesystem or Logical Volume backup may now contain more
than one filesystem or logical volume. If more than one object is
selected to backup, the backup, similar to the volume group backup,
will contain multiple images, each containing a separate filesystem
or logical volume.
This enables the simplicity and flexibility of using a single command
or operation to backup multiple filesystems or logical volumes, and
restore only a single object from the backup.
The Filesystem backup is much different in format than previous versions
of Sysback. Instead of being backed up using the AIX "backup" by
inode, the filesystem backups will contain a backup by filename,
as do other backup types. This was done for the following reasons:
1. Files are are now defragmented during restores. Previous restores
from an inode backup preserved filesystem fragmentation which adversely
affected I/O performance.
2. More flexibility of selective restores of files to different directories
3. Files or directories may now be excluded from filesystem backups.
Previously, the exclude list was ignored for filesystem backups.
4. "Stacking" previous backups on tape was difficult and required multiple
rewinds when reading from the backups.
The incremental backups provided by the former filesystem backup
options are still available as described in the next section.
Incremental Backups
-------------------
Incremental backups may now be performed for both Volume Groups and
Filesystems. Sysback will keep track of the last time a backup was
performed at a certain incremental level for each volume group and
filesystem. Sysback will also keep track of the contents of the filesystem.
If a file has been removed from the system between the time the previous
and current incremental backup was performed, that file will be automatically
re-removed by Sysback when the current incremental backup is restored.
As in previous versions, there are multiple incremental backup levels.
A level "0" indicates a backup of all files. Level "1" indicates
backup of files since the last level 0. Level "2" indicates backup
of files since the last level 1, etc.
Individual files or directories may be restored from any incremental
backup level. When restoring all files from an incremental backup
level, the user must indicate that this is an incremental restore
if they wish previously removed files to be re-removed at the end
of the restore.
To perform an incremental backup, the user must enter the incremental
backup level in the "Incremental backup level" field in SMIT, or
use the "-i level" option at the command line. If no incremental
level is entered, the backup is assumed NOT to replace any previous
incremental levels performed.
Restore from Backups
--------------------
There have been considerable enhancements to the restore of Sysback
backups. Instead of having a separate option to restore from each
backup, a single SMIT option, and a single "sysrestore" command is
now used to restore any type of data from any backup type. Sysback
will identify the backup type by reading the header on the backup,
and SMIT will present a list of applicable types of data to restore
based on the backup type. The restore data type will be one of the
following:
Volume Group
Logical Volume
Filesystem
Directory
Regular File
When restoring from SMIT, the user must select one of the above data
types, and will then be presented with a list of the available objects
of the selected type on the backup. The user may then select one
or more of those objects to restore.
If a System or Volume group backup contains multiple volume groups,
you may select to restore one or more volume groups in a single operation.
Likewise, from a System or Volume Group backup, you may restore one
or more filesystems, logical volumes, files or directories.
The following are enhancements to the restore process:
1. Faster restore of individual filesystems, files ore directories from
System and Volume Group backups.
2. Restore of multiple objects (i.e. volume groups, logical volumes,
filesystems, etc) in a single operation.
3. Recovery of filesystem and logical volume data from System and Volume
Group backups even after a tape I/O error.
4. Restore of a select filesystem from System and Volume Group backups
restores only the filesystem requested, and not any data for other
filesystems mounted beneath the requested filesystem.
Recreate Volume Groups, Logical Volumes, or Filesystems
-------------------------------------------------------
As with the restore options, there is now only one option needed
to recreate volume groups, logical volumes or filesystems from a
backup. In addition, one or more objects may now be recreated in
a single operation.
A new user interface is available for changing the volume group,
logical volume or filesystem attributes, locations and sizes before
they are created. This new user interface is identical to that used
during the System Installation Process documented later.
Exclude List
------------
The exclude list options in SMIT now allow a logical volume name
to be entered as well as a file or directory name. If a logical volume
name is entered, the data for that logical volume will be excluded
from all backup types.
Backup Sequence Number ("stacking" backups)
-------------------------------------------
The ability to "stack" multiple separate backups to a single tape
or series of tapes is handled differently in this version of Sysback
than it was in earlier versions. This need was brought on primarily
by the differences in the format of the backups.
A System or volume group backup, for instance, contained only one
tape "image" on earlier Sysback versions. Since the user had only
the ability to perform a backup of one volume group at a time, it
was easy for the user to know that to restore the third volume group
backup, this was the third image on the tape.
Sysback now places many images on tape for a single volume group
backup. In addition, a single filesystem backup operation may contain
multiple filesystems. The user can no longer determine how many "images"
are on the tape based on the number of backup operations performed.
Therefore, the Sysback List, Verify, Recreate and Restore operations
allow the user to enter a "Backup Sequence Number". This option replaces
all instances in which the user was previously asked for the "Image
number on tape". The user need only know the backup number (i.e.
the third backup performed), and Sysback will determine the number
of tape images to skip to move to the correct backup before beginning
the desired operation.
Read Volume Label
-----------------
This option now appears on the Backup & Recovery Options menu in
SMIT. This single option replaces both the prior Read Volume Label
option in the Utilities menu and the List Files on Backup option
for each backup type. When this option is selected, you will be asked
whether you wish to:
1. Display detailed information? If "yes", the list will include both
the main backup header information as well as a list of each image
contained in the backup. A separate image is displayed for each filesystem
or logical volume included on the backup.
2. Show Filelist? If "yes", and the backup contains any regular files
or directories, the list of directories and files (each in a separate
list) will be displayed as well.
The readsbheader command is used to list all of the above.
Progress Indicator
------------------
The progress indicator has been improved so that a single indicator
will be displayed for an entire backup, even if that backup contains
multiple volume groups, logical volumes or filesystems.
Network Support on Bootable Tapes
---------------------------------
Network installation support is no longer added to bootable tapes
by default. It is assumed that the system will be installed from
tape if the system is booted from tape. However, this may be overridden
by selecting the type of network support to add to the boot tape.
This option is now provided separately since the addition of FDDI,
and the growing size of network support files requires too much memory
for the System Installation process to be performed.
When choosing the SMIT options to either "Backup the System (installation
image)" or "Create a Bootable Tape (without data)", an option entitled
"Network install support to include" will appear. Here you may select
a network type of either Ethernet, Token-ring or FDDI.
New Features
============
New System Installation Process
-------------------------------
The System installation process has been completely redesigned to
include the following new features:
1. Improved User Interface
The menus which display during the installation process have been
redesigned to provide a more visual, user-friendly, flexible, and
faster way to make and change selections. Help information is provided
on-screen for all selections.
Cursor keys or the tab key may be used to move the highlighted selection,
and Enter to select. Refer to the section "New User Interface for
Editing LVM Information" below for additional information on the
menus provided for changing the installation settings.
2. Even More Customizable Installation Options
When selecting to change the installation settings, the user may
now change any of the following information:
a. Logical volume names - Logical volume data will be restored to the
new logical volume name, and the filesystem information, if any,
will be updated to reflect the new logical volume.
b. Logical volumes may be moved to new volume groups. The logical volume
or filesystem will be created and restored to the new volume group,
and a new journaled filesystem log, if required, will be assigned
to the filesystem.
c. Filesystem Mount points - data for the filesystem will be restored
to the new location.
d. Exclude a logical volume or filesystem from install. Doing so will
also prevent the filesystem or logical volume data from being restored.
e. User may change the filesystem attributes for support of Large Files
and Allocation Groups. These options will only appear on AIX Version
4.2 or later systems.
f. User may turn on or off concurrent volume group support (for shared
volume groups).
g. User may now change the logical volume attributes for mirror-write
consistency checking, write-verify, bad block relocation, relocatable,
and maximum physical volumes.
3. FDDI Network Installation Support
If booting from tape, it is necessary to explicitly select to include
network support on the bootable portion of the tape. For network
boot, an FDDI network boot image must be created using the same steps
required for other network types.
4. Raw Logical Volume Data
Raw logical volume data included on the System backup will be restored
to the raw logical volumes upon installation. Raw logical volumes
may be excluded from the installation by selecting not to create
the logical volume, and therefore, the data on the backup will be
ignored.
5. Better Recoverability
The base operating system (root [/] and /usr filesystems) are restored
independent of other filesystems. After the restoration of the base
operating system data, the system is configured and made bootable.
Once this occurs, the system may be booted in normal mode. Therefore,
any installation error, even a complete power loss, will not prevent
the system from being booted normally. Once a system has been booted
normally, any volume groups not created or data not restored during
the installation process may be recovered from the backup using the
SMIT menus.
An I/O error occurring during the restoration of a filesystem or
logical volume will NOT cause the installation to fail, but the remainder
of the filesystem or logical volume data will be skipped and the
rest of the data will be restored normally. Once the system is up
and running, steps may be taken to recover the data in error.
Considerable debugging and error recovery facilities have also been
implemented to provide information necessary to recovery from other
potential installation problems.
Power Installation Process
--------------------------
When creating a System Backup, an option is provided for making the
backup a "Power" Backup. A Power Backup differs from a System Backup
in that all filesystems are backed up as "raw" logical volumes. This
will often double the backup performance. The primary benefit is
that the installation performance can be as much as 3 times faster,
since logical volumes are restored as sequential "raw" data rather
than having to restore to filesystem blocks and frequently update
the journaled filesystem log.
There are limitations, however, to the flexibility of the installation
process when using a Power System Backup:
1. Since all filesystems are backed up as raw logical volumes, the entire
LV is backed up even if only 1/4 of the filesystem is used. If this
were the case with all filesystems, the backup and install would
likely take longer than normal.
2. It is only possible to restore raw logical volumes from this backup.
Therefore, when choosing to restore select data from the backup,
you will only be allowed to restore an entire LV and only if that
LV is inactive. This obviously means that you cannot restore any
individual files or directories, only entire filesystems, and no
filesystems, such as /, /usr and /var can be restored since they
are always active.
3. When installing or recreating VGs or LVs from this backup, you cannot
change the following attiritutes:
a. any filesystem attributes
b. logical volume name
c. logical volume size
d. the volume group in which an LV is to be created
New User Interface for Changing LVM Information
-----------------------------------------------
A new user interface is provided for changing the LVM information
used to recreate volume groups, logical volumes and filesystems.
All features of prior versions of Sysback are still provided. New
features are also provided as descried in the section "New System
Installation Process" earlier in this section.
The same process for changing LVM information is used when either
recreating a volume group or logical volume on an active system or
when reinstalling the system from a System Backup.
The new user interface uses Curses, a terminal-independent programming
interface, which allows for screen-wide cursor positioning, use of
editing keys, etc. The new user interface allow selections to be
made by moving a highlighted bar with the arrow or tab keys, and
data fields to be changed using insert and delete keys, etc.
As logical volumes characteristics are changed, or when adding or
removing physical volumes from a logical volume or volume group,
the space required and available within a volume group is updated
to assist the user in making decisions as to logical volume and filesystem
sizes, etc.
A help box is always shows at the bottom of the screen, displaying
a description of the current highlighted field, and the available
options for changing the current value.
Offline Mirror Backups
----------------------
Whenever a backup is performed, the data at the beginning of the
backup will be considerably older than the data at the end of the
backup. This could cause considerable problems in a relational database
environment after the data was restored, since records in different
files that should be updated concurrently would then show only
partially-updated transactions. On the other hand, in an environment
with large amounts of data that must remain accessible in a 24-hour
]operation, simply stopping transactions during a backup is also not a
valid option.
This new process will perform backups of mirrored logical volume
data after "breaking" off a copy of each logical volume and using
the offline copy to obtain a backup of non-changing data. The remaining
"active" copy of the data remains completely accessible to the users
without interruption throughout the backup process. When the backup
is complete, the mirrors are put back together and only the physical
partitions from the broken mirror that became stale while it was
offline are updated.
The resynchronizing of only "stale" partitions is particularly important,
since resynchronizing all of the partitions after returning the offline
copy would require a great deal of time and system resource, often
seriously affecting the overall system performance for several hours.
In this case, only physical partitions on the disks which were written
to while the mirrored copies were offline would need to be re-written.
IMPORTANT NOTE: This process is intended for taking offline inactive
logical volumes and unmounted filesystems. Only then can we be sure
that the data contained in those logical volumes and filesystems
is up to data and no transactions were in process when the logical
volumes were taken offline. It is also understandable that it is
not always possible to make logical volumes and filesystems inactive
before taking the copies offline. Yet it is important to note that
the integrity of relational data cannot be guaranteed if applications
are not quiesced, and the integrity of a filesystem cannot be guaranteed
if filesystem data is changing at the time the mirror is taken offline.
Although unlikely, filesystem integrity compromised by taking a
mounted filesystem offline may cause system errors or failure.
Selectable Filesystem Data Backend Command
------------------------------------------
The backup command set to use may be changed by selecting the option
"Select Filesystem Data Backup Command" from the "Utilities" options
on the Sysback Main SMIT menu. After selecting the command, this
command will be used for all Sysback backups involving filesystem
files (not logical volume backups). Upon restore from any Sysback
backup, Sysback will automatically detect the backup type and use
the appropriate corresponding restore command to restore the data.
NOTE: The backup command is the default and should not be changed
unless another command provides needed function that the backup command
does not.
Although Sysback creates a data format all its own in order to store
information regarding the backup contents and system information,
and to allow multi-copy and striped backups, the underlying command
used to perform filesystem backups in earlier versions of Sysback
has always been the AIX "backup" command.
The backup command was selected because of its flexibility over other
commands and because it backs up data regarding files such as the
access control list (ACL) and the trusted computing base (TCB).
The backup command, however, has changed over time in how it backs
up and restores "sparse" files. A sparse file is a file in which
blocks of data have been written non-sequentially, leaving unallocated
blocks in the middle of a file. Previous levels of the backup command
did not preserve this sparseness, and a sparse file, upon restore,
was expanded to include all blocks in the middle of the file, often
causing a filesystem to inadvertently run out of space. The backup
command was later changed to preserve this sparseness, but this is
often a problem for customers experiencing the opposite affect.
If a file is created and all blocks are allocated by writing nulls,
or "0"s throughout the file, these blocks of data are not preserved
during a restore, since the goal is to preserve sparseness, indistinguishable
from a file containing null blocks. The affect is that a file created
at a large size could be restored to a very small size.
Sysback resolves this issue by allowing the user to select which
command is to be used to perform backups. This may be either the
AIX backup and restore commands (which preserve sparseness) or the
tar command (which does not).
Set Network Attributes for Sysback Backups and Restores
-------------------------------------------------------
By tuning certain network parameters, it may be possible to increase
the performance of Sysback backups and restores. This option makes
it possible to set certain values which affect network performance
during Sysback backups and restores without affecting network performance
of other processes using the same network.
IMPORTANT NOTE: You should not change the network settings using
this option unless you are familiar with network tuning. Also, it
is imperative that the same settings be applied to both the Sysback
server and client hosts or network backups will often lock up.
The changes applied here will affect all backups, verifies, and restores
performed within Sysback, but will NOT apply to a Sysback system
installation. This is because it is not possible to query the values
set during the installation process.
Create or Edit an LVM Information File
--------------------------------------
An LVM information file is created by the mkvginfo command as part
of all Sysback backups which contain LVM (logical volume manager)
information. This file is then used either when re-installing the
system from a backup or recreating a volume group, logical volume
or filesystem from a backup.
At times you may wish to create your own LVM information file and
tailor it to your needs. This customized LVM information file may
then be placed on the backup by using the -g flag to either the sysback,
mkvgback, mkjfsback or mklvback commands. The customized LVM information
file may also be used to replace the information on a System Backup
during a System installation by creating a customized installation
diskette as described in the next section.
To either edit an existing LVM information file, or to create a new
LVM information file from the information on the current system and
edit the new file, select "Create or Edit an LVM Information File"
from the Utilities Options menu, or refer to the mklvminfo and editlvminfo
commands.
You will be provided with a menu-driver interface for changing the
information in the file. This new user interface is identical to
that used during the System Installation Process and when recreating
a volume group or logical volume on an active system. This user interface
is described earlier in the section "New User Interface for Editing
LVM Information".
Create Customized Installation Diskette
---------------------------------------
A customized installation diskette may be created which may contain
any of the following:
1. LVM Information File - You may select to include a customized LVM
information file. This will replace the LVM information contained
on the backup, and is typically used to apply many changes to the
LVM information without requiring the user to do so using the installation
menus.
2. Pre-installation script - this script is executed prior to the Sysback
menus appearing during the installation process. This may be used,
for instance, to restore other information from the diskette, or
to perform some special system configuration not ordinarily performed
by the installation process.
3. Post-rootvg installation script - this script is executed after the
files for the rootvg volume group are restored. This is commonly
used to execute the sample script
"/usr/lpp/sysback/scripts/install.postroot_hwmigrate",
provided with Sysback, to perform an automatic installation of device
code from CDROM not already included in the system restored from
the backup media.
4. Post installation script - this script is executed at the end of
the installation process before the system reboots. This may be used,
for instance, to execute the sample script
"/usr/lpp/sysback/scripts/install.post_rmnet",
which removes the network configuration from the restored system
data to prevent any prompts at the end of the Sysback install process.
More information on the installation scripts may be found in the
Sysback User and Reference Manual in the section entitled "Creating
Scripts for Customizing the System Backup and Installation Process".
Once this diskette has been created, it need only be inserted into
the diskette drive during the system boot process. It will be automatically
read, and any of the above information files provided will be used
during the installation process, overriding the same information
on the backup media if it exists..
New AIX and Device Support
--------------------------
Sysback Version 4 will support the following new features of AIX:
1. Large File Support - Sysback will retain the large file support
characteristic of a filesystem when recreating a filesystem on a
running system or when reinstalling from a Sysback backup.
In addition, it is now possible to perform a Sysback backup to a
disk file that is larger than 2 gigabytes in size, provided that
the filesystem being written to was created to support "Large Files".
If Large File support is desired for a pre-existing filesystem, the
filesystem must be backed up using Sysback, deleted, recreated and
restored. During the process of recreating the filesystem, the Large
File support may be enabled from the menus.
2. Filesystem Allocation Groups - Filesystem allocation group characteristic
of a filesystem will be retained when recreating a filesystem on
a running system or when reinstalling from a Sysback backup.
3. FDDI networks - Sysback will support FDDI networks for all backup
and restore operations, and for network boots and network installation.
4. Concurrent Volume Groups - This characteristic is used for volume
groups shared between more than one system. Sysback will retain or
allow changes to this characteristic when recreating a volume group
on an active system or when reinstalling from a System Backup. Sysback
will also retain the volume group major device number, which must
usually be the same between all systems in which a volume group is
shared.
===============
Command Changes
===============
Obsolete commands
-----------------
The following commands have been removed from the product as their
use has been replaced by new function in the product:
1. fsback.pre_lvbackup, install.post_lvrestore
These "sample" pre-backup and post-installation scripts, found int
he /usr/lpp/sysback/scripts directory, were used in Sysback Version
3 to append raw logical volume data to the end of a System Backup
and automatically restore that logical volume data at the end of
the System Installation process. Since raw logical volume data is
now included in the System and Volume Group backups in Sysback, it
is no longer necessary for the user to customize the backup and install
process to do so.
2. dirrestore, lvrestore, jfsrestore, vgrestore
These commands were used in Sysback Version 3 for listing, verifying
and restoring data from different types of Sysback backups. In Sysback
Version 4, the single command, sysrestore, is used to verify or restore
from all types of backups, and the readsbheader command is used to
list the files contained on the backups. Refer to these commands
in the "changes" section below.
Changes to existing commands
----------------------------
The following is a list of commands in which existing command line
syntax has changed or new flags and arguments have been added:
1. mkdirback, mklvback, mkjfsback, mkvgback, sysback
These commands have all been modified with the following changes:
a. -f [ device | file | directory ] flag and argument changed to allow
entry of a directory for the destination. If a directory is specified,
the file is written to the directory with the filename constructed
as follows:
Type.Hostname.id
where "Hostname" is the local host name (or "localhost" if none),
id is the ID entered with the -I flag, and "Type" is the type of
backup and must be one of one of:
SB - System Backup (or Power Backup)
VG - Volume Group backup
LV - Logical volume Backup
FS - Filesystem backup
FD - File/Directory backup
If the -f flag is used to specify the full pathname of a file, the
prefix of the filename MUST be one of the above types.
b. -g filename flag added to all commands above except mkdirback for
specifying the name of an LVM information file. The LVM information
file is not used on a file/directory backup. On all other backups,
it is used to store LVM information needed to recreate volume groups,
logical volumes and filesystems. Also, see information on the -g
flag under the sysback command.
c. -I id flag and argument added for specifying the "ID" portion of
the filename when writing to a disk file. This is used in conjunction
with the -f directory option
d.-O flag added for overwriting existing backups to disk file with
same name
2. sysback
This command has been further modified as follows:
a. -N [ ent | tok | fddi ] flag and argument added to allow network
support to be added to a bootable tape. This flag has no meaning
unless writing the backup to tape. In Sysback version 3, network
support was always included on tape to allow a user to boot from
tape, then perform a network install. This support is now optional,
and only one network type may be specified, since only one network
adapter may be used to perform a network install. If this flag is
omitted when a bootable tape is created, it will only be possible
to install from tape.
b. -g flag now requires a filename to be specified. The -g flag used
to take no arguments, and it was assumed that the LVM information
file was named /usr/config/vginfo. Now, similar to the other backup
commands, the -g flag requires that the name of an LVM information
file be specified.
c. -P flag added to create a Power System Backup. This type of backup
stores all filesystem data in raw logical volume format to allow
faster backups and restores. -P option should not be used if changes
to any filesystem information will be required when reinstalling
from the backup.
3. mkjfsback, mkvgback
For both commands, the "-l level" option may be used to specify an
incremental level to backup. The level parameter may be a number
between 0 and 9. Level 0 indicates a backup of all files in the filesystems
and/or all logical volumes in the volume groups. Level 1-9 indicates
only the files in the filesystems and/or logical volumes in the volume
groups which have been changed since the last previous level backup
will be backed up. A previous level backup can be any level number
between 0 and the current level number specified.
The mkjfsback command now backs up filesystem files similar to other
Sysback backup commands, whereas in Sysback Version 3, mkjfsback
backed up files using the backup-by-inode format of the AIX backup
command.
In the case of the mkjfsback command, the use of the level option
does not differ from Sysback Version 3. However, for either command,
if the option is omitted, no incremental backup level will be recorded,
and all files in the filesystems and/or logical volumes in the volume
groups will be backed up.
4. mkdirback
The -D and -F flags have been removed and are no longer valid. The
-F flag used to indicate that the backup should not parse into a
different filesystem. This is obsolete, since a backup of a filesystem
may now performed with the mkjfsback command instead, and the files
are backed up in the same format and have the same restore options
as with the mkdirback command.
5. remakevg
The -E flag has been added to indicate that the user wishes to be
presented a screen for making changes to the LVM information prior
to the actual creation taking place. Without the -E flag, it is assumed
that no changes will be made unless there is a requirement due to
differences in the device configuration. If the -q flag is also specified,
no prompts will be provided, and the creation will take place upon
execution of the command without user interaction.
The -F flag is no longer used. This flag used to indicate if the
backup was a System Backup. The remakevg command now detects the
type of backup without this flag.
The remakevg command has also been modified to allow multiple volume
groups and or logical volumes and filesystems to be created with
one command. The syntax of the command has changed slightly as a
result. The -v or -l flags no longer require a logical volume or
volume group name be specified after the flag. Instead, you must
specify either the -v or -l flag alone, or with other flags, then
append the list of volume groups or logical volumes to be created
to the end of the command.
For example, to create the uservg1 and uservg2 volume groups from
a System or Volume Group backup in the tape drive, with no prompting,
the following command would be used:
remakevg -vqf /dev/rmt0 uservg1 uservg2
6. sysrestore
The sysrestore command has been modified extensively to add new function
and to combine the function of numerous previous commands into a
single robust command. The changes in this command syntax are likely
to require changes to any custom scripts created by users to either
list, verify or restore data from backups.
The sysrestore command replaces the dirrestore, lvrestore, jfsrestore,
vgrestore and sysrestore commands in Sysback Version 3. The sysrestore
command automatically detects the type of backup, so it is not necessary
to have different commands. However, there are different types of
data that may be verified or restored from a single backup. Therefore,
the -t option must be specified to indicate the type of data to verify
or restore.
For instance, a volume group backup may contain multiple volume groups,
filesystems and raw logical volumes. If it is desired to restore
2 specific filesystems from the backup, you must specify the -tF
flag, and the data_list argument at the end of the backup would contain
the mount points of the filesystems to restore. If you wish to restore
only a specific directory from a backup, regardless of the backup
type, you must specify the -tD flag, and the data_list argument would
be the directory or directories to restore.
The specific changes from prior use of the sysrestore command is
as follows:
a. -t type flag and argument required to specify type of data to verify
or restore.
b. -F flag added to allow restoration of system directories or files
that are not ordinarily replaceable, such as the /usr filesystem
or the /etc/objrepos directory. Restoring this type of data can have
adverse affect on the system or even cause a system failure, so should
be used with extreme caution.
c. -H flag added, and will display the above usage message on the screen
d. -L flag used to list the files on the backup. This flag will now
list any of the following, depending on the contents of the -t argument:
-tV Volume groups
-tL Logical volumes
-tF Filesystems
-tD Directories
-tR Regular Files
-tf Directories and regular files
-tl Filesystems and logical volumes
e. -T flag queries the type of backup and returns one of the of the
following single characters:
S System Backup
P Power System Backup
V Volume Group Backup
F Filesystem backup
L Logical Volume Backup
D File/Directory Backup
f. -V flag replaces the former -l flag for verifying the backup. When
specified, the data on the backup is read but no data is restored.
It is still necessary to specify the type and which data to verify.
For instance, you may wish to verify only a couple of raw logical
volumes on a volume group backup. To do so, specify the -V flag,
the -tL flag, and the names of the logical volumes to verify for
the data_list argument. To verify the entire contents of a System
backup, you may specify the -V flag, the -tV flag, and the names
of all volume groups to verify.
g. -y flag added to allow restoration of incremental data. If you wish
to restore the entire contents of an incremental backup, this flag
must be specified if you want the resulting filesystem(s) to contain
the same files as it did at the time the backup was created. This
may, in some cases, require files to be re-removed from the filesystem
that were deleted prior to the incremental backup level being performed.
h. -i sequence flag replaces the prior -i image flag for restoring from
different "stacked" images on the backup. Since a single Sysback
backup often now contains multiple "images", it is not necessary
for the user to know which image contains the data they require.
Instead, if multiple backups are stacked onto a single tape, the
user need only specify the sequence number of the backup to be listed,
verified or restored, and this command will automatically forward
the required number of images to reach the desired backup.
i. The data_list argument may be a list of either volume groups,
filesystems, logical volume names, directories or file names,
depending on the type of data to be listed, verified or restored
(as indicated by the -t flag).
7. readsbheader
The readsbheader command, used to list the header information on
a backup, has been expanded to produce additional information. The
following flags have been added to this command:
a. -d flag added to indicate that the user wishes to also produce a
list of the logical volumes and/or filesystems contained on the backup,
if any.
b. -l flag added to indicate that the user wishes to also produce a
list of files and directories contained on the backup, if any.
c. -n option added to prevent a tape from rewinding prior to start of
this command. This assumes the tape is positioned at the start of
the desired backup.
d. -q option added to produce the requested information without status
messages.
New commands
------------
There are numerous new commands provided as part of the Sysback package.
Of those, only the following will be documented, as others are used
internal to the product and not intended for customer use.
1. editlvminfo
This command may be used to edit the contents of an LVM information
file. The command will look at the file to determine its type and
contents. The maintenance screens used for changing the LVM information
prior to recreating volume groups and filesystems or reinstalling
the system will be presented. Refer to "New User Interface for Editing
LVM Information" in the New Features section for additional details.
2. sbom_backup
This command is used to take physical volumes offline in order to
gain access to offline mirrored logical volumes. This command is
only available if the Offline Mirror Backup feature of Sysback is
installed. Once mirrors are taken offline, this command may be called
upon to automatically execute a pre-defined backup script and return
all mirrors and physical volumes to their original status when complete.
A query may also be performed to "preview" the status of the physical
volumes and volume groups before actually taking the physical volumes
offline. In this case, no action will be performed, but the volume
groups and physical volumes entered will be checked and a list of
errors, if any, or logical volumes for which copies will be taken
offline, will be produced.
Refer to "Offline Mirror Backups" in the New Features section for
additional details.
*ACTION PLAN:
Closing with customer approval
TEST CASE:
Response:
Response:
Closing with Customer Approval
Support Line: What is the difference between sysback ver 3 and sysback ver 4.1 ITEM: BX0549L
Dated: April 1997 Category: N/A
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