btextract(8)						      System Manager's Manual						      btextract(8)

NAME

       btextract - Extracts the file systems from tape in single-user mode in memory

SYNOPSIS

       /usr/sys/bin/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 duplicate 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.
       Instead, the btextract utility restores file systems using the disk partition information gathered during the btcreate session; all  exist-
       ing 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 assigns the b partition of the root disk as the swap partition.

       A file system which is more than 100% full cannot be restored in a partition 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/dsk8h	   83812      83786	      0   112%	  /bootable

       The file system is 112% full. This file system cannot be restored on the target file system of 86758 (512-blocks), as the following 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 solution 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, initialize 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 BOOTDEV.

       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 custom_install.sh script before exiting. See the btcreate reference page for
       more information.

       You also have the option to label disks using your own disklabel script.   If a customized disklabel script is not present,  the  btextract
       command will label the disks in the usual manner.   A customized disklabel script has the following restrictions: It must be located in the
       /usr/lib/sabt/etc directory.  It must be named custom_disklabel_file.

       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

       Success.  An error occurred.

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
       image A custom disklabel file read by btextract

SEE ALSO

       Commands:  addvol(8), btcreate(8), df(1), disklabel(8), lmf(8), mkfdmn(8), mkfset(8), newfs(8), restore(8), sh(1), vrestore(8)

																      btextract(8)