Air Cleaner User Manual

sbread
Purpose
Reads data from all SysBack backup types.
Syntax
 sbread
-a
-c ″device″
-e
-v
-x
-H
-L
-P
-T
device 
Description
The sbread command is used to read a backup that was created using the sbwrite
command. All SysBack backups are written to the media using sbwrite, and all
SysBack restore programs use sbread to retrieve the data from the media. In
addition, SysBack uses sbwrite to store the table of contents (LVM information),
file list, and other information identifying the type and contents of the backup.
This information can then be retrieved using the sbread command.
The device parameter can be one or more tape drives, a virtual device, or a dash (-)
indicating that the input should be received from standard input (stdin).
The sbread command reads data only from backup devices or directories to which
the local host and user has access, as defined by the cfglocaccess or cfgremaccess
commands. When sbread is executed locally, the access permissions are checked in
the .local_access file. When executed by the sbclient command on a remote host,
the remote host and user access permissions are checked in the .remote_access file.
By default, sbread assumes the data was backed up with sbwrite using a
sequential write policy. If you used a virtual device name to perform the backup,
you can use the same virtual device name to read the backup. Otherwise, if you
are reading from a backup created with a parallel write policy, you must specify
the -P flag to the sbread command. Also, when reading from a backup made using
a parallel write-policy, you must also specify the same number of devices to read
the data as was used to create the backup.
SysBack backups, with the exception of the raw logical volume backups, are
formatted using either the AIX backup or tar command. The resulting data is sent
to the sbwrite program, which stores the data on the media, including the backup
header, table of contents (LVM and filesystem information) and file list, if specified.
To read the same backup, it is necessary to use the sbread program to read the
data from the media and send the results to the AIX restore or tar program to be
unformatted and placed in the AIX filesystems.
When you use the -H, -T,or-L options with a no-rewind tape device name, the
data is read from the beginning of the backup media and the tape is repositioned
at the beginning of the same backup image. By omitting the -H, -L and -T flags, it
Appendix A. Commands A-71