Air Cleaner User Manual

is assumed you are to read the actual data from the backup image. You can
compress data before writing to the media. If compressed data is written to the
media, the data must be uncompressed before it is restored to disk. The SysBack
backup programs compress data using sbcomp and also indicate to sbwrite that
the backup is compressed by using the -p flag. Before reading a backup with
sbread, you can query whether the data was compressed by reading the backup
header (sbread -H). If Packed: Y is shown, you should uncompress the data as it is
output by sbread using the sbuncomp program.
If the data you want to read is not contained in the image the tape is currently
positioned to, you must use the sbfwd command to forward the tape to the correct
image before reading.
Flags
-a Indicates the device is an auto-loader. This flag suppresses the volume prompt,
requesting that the user change tapes. Instead, a message indicates the tape is
unloading and waiting for next volume. The reading continues automatically
when the autoloader has inserted the next volume.
-c “termdev”
If the backup contains multiple tape volumes, the volume prompt is sent to the
“termdev” device (such as /dev/tty0).
-e Indicates all devices (if tape) should be rewound upon completion. The default
action is to not rewind.
-v Indicates whether status messages should be displayed at the beginning and
end of the backup.
-x Displays the progress indicator when reading the data.
-H
Indicates the header information should be read from the backup. If using a
no-rewind tape device, the tape will be repositioned to the beginning of the
same image when completed.
-L
Reads the file list from the backup, if it exists. If using a no-rewind tape
device, the tape is repositioned to the beginning of the same image when
completed.
-P
Indicates the backup was performed with a parallel write-policy, so all
specified devices should be read synchronously. If not specified, a sequential
write-policy is assumed, and only the first device in the list is read unless the
end of media is encountered.
-T
Reads the table of contents (LVM and filesystem information) from the backup,
if it exists. If using a no-rewind tape device, the tape is repositioned to the
beginning of the same image when completed.
Examples
1. To read the contents of a compressed sequential backup created using the
sbwrite command to virtual device vdev1, saving the results in a file called
/tmp/file, type:
sbread vdev1 | sbuncomp > /tmp/file
A-72 IBM Tivoli Storage Manager for System Backup and Recovery: Installation and User’s Guide