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Command: btextract | Section: 8 | Source: Digital UNIX | File: btextract.8.gz
btextract(8) System Manager's Manual btextract(8)
NAME
btextract - Extracts the file systems from tape in single-user mode in
memory
SYNOPSIS
/sbin/btextract
DESCRIPTION
The btextract utility is a shell script that restores file systems from
tapes that contain the bootable Standalone System (SAS) kernel. The
SAS kernel is created using the btcreate utility. You can perform a
DEFAULT restore or an ADVANCED restore operation.
A DEFAULT restore is used by system administrators who want to dupli-
cate the customized system on more than one machine of the same hard-
ware platform type. When you perform a DEFAULT restore, you cannot
specify which disk partitions to use for the restore operation. In-
stead, the btextract utility restores file systems using the disk par-
tition information gathered during the btcreate session; all existing
information is overwritten.
Note
To perform a DEFAULT restore, the disk configuration of
the system you backed up must be the same as the system
you are restoring.
During an ADVANCED restore, you are prompted to enter the name of the
disk partition where the file systems are to be restored.
Note
During an ADVANCED restore, the btextract utility as-
signs the b partition of the root disk as the swap par-
tition.
A file system which is more than 100% full cannot be restored in a par-
tition of the same size as the original partition. During the restore
of the UFS file system, the /sbin/restore command adds a new file named
restoresymtable. The presence of this restoresymtable file can make
the restored file system larger than the source partition size listed
in the /sbin/disklabel output.
For example, on the source system, the disklabel shows the target h
partition to be: h: 86758 1212416 4.2BSD And the ufs file system
is as follows: Filesystem 512-blocks Used Available Capacity
Mounted on /dev/rz8h 83812 83786 0 112%
/bootable The file system is 112% full. This file system cannot be re-
stored on the target file system of 86758 (512-blocks), as the follow-
ing file is created by the /sbin/restore command. -rw-r--r-- 1 root
system 27368 Jul 2 09:33 restoresymtable The command /sbin/restore
creates a restoresymtable file that exceeds the 112% range. The solu-
tion is to use a partition of about 86996 (512-blocks), about 3.8%
larger than the actual file size.
USING btextract
To use the btextract utility, place the system in a halt state, ini-
tialize the system, then boot from the tape as follows: >>> init >>>
show dev >>> boot -fl "nc" MKA500 In the previous example, the show dev
command provides the device name under BOOTDEV and MKA500 is the BOOT-
DEV.
Once the initial boot is complete, the shell invokes the btextract
utility. If you created a /usr/lib/sabt/sbin/custom_install.sh script
during the btcreate session, the btextract utility invokes the cus-
tom_install.sh script before exiting. See the btcreate reference page
for more information.
After the btextract utility completes, you must shut down the system,
then reboot the system from the restored disk as follows: # shutdown -h
now >>> boot DKA100 In the previous example, DKA100 is the BOOTDEV.
RETURN VALUES
The btextract utility returns zero (0) on success and a number greater
than zero (0) on error.
FILES
Log of the btextract process in memory Copy of the btextract process on
the restored root file system Script used to customize the restored im-
age
RELATED INFORMATION
Utilities: addvol(8), btcreate(8), df(1), disklabel(8), lmf(8),
mkfdmn(8), mkfset(8), newfs(8), restore(8), sh(1), vrestore(8) delim
off
btextract(8)