btextract man page on DigitalUNIX

Man page or keyword search:  
man Server   12896 pages
apropos Keyword Search (all sections)
Output format
DigitalUNIX logo
[printable version]

btextract(8)							  btextract(8)

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


       The btextract command 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.

       Use  the	 default restore option when you want to duplicate the custom‐
       ized system on more than one machine  of	 the  same  hardware  platform
       type.   When  you  perform  a default restore, you cannot specify which
       disk partitions to use. Instead, the btextract  command	restores  file
       systems using the disk partition information gathered during the btcre‐
       ate session. The restore operation overwrites all existing  information
       on the target drive.


       To  perform  a default restore operation, the disk configuration of the
       system you backed up must be the same as the system you are  restoring.
       Use the diskconfig GUI or the disklabel and newfs commands to prepare a
       disk to receive the extracted tape contents.

       During an advanced restore operation, the btextract command prompts you
       to enter the name of a disk partition. The file systems are restored to
       the specified partition.


       During an advanced restore operation, the btextract command assigns the
       b partition of the root disk as the swap partition.

       You  cannot restore a file system that is more than 100% full to 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 output from the /sbin/disklabel command.

       For example, on the source system, the disklabel	 shows	the  target  h
       partition to be:

       h:    86758  1212416    4.2BSD

       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 blocks (512-byte blocks), because the
       following file is created by the /sbin/restore command.

       -rw-r--r--   1 root   system   27368 Jul	 2 09:33 restoresymtable

       The /sbin/restore command creates a restoresymtable file	 that  exceeds
       the  112%  range.   The	solution  is to use a partition of about 86996
       (512-byte 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 preceding example, the show dev command provides the device name
       under BOOTDEV, and MKA500 is the BOOTDEV.

       After  the  initial  boot  is complete, the shell invokes the btextract
       command. If you created a  /usr/lib/sabt/sbin/	script
       during  the  btcreate  session,	the btextract command invokes the cus‐ script before exiting. See btcreate  for	more  informa‐

       You  can	 optionally label disks using your own disklabel script.  If a
       customized disk labeling script is not present, the  btextract  command
       labels  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 command completes, you must shut down the system,
       then reboot the system from the restored disk as follows: # shutdown -h
       now >>> boot DKA100

       In the preceding example, DKA100 is the BOOTDEV.

   Creating a Custom Prerestore File
       When  you  boot	a  system  using  bootable tape, the btextract command
       prompts you to create an answer file that provides the minimum informa‐
       tion  needed  to	 complete  the	boot  and restore operation. This cus‐
       tom_prerestore file is a text file  located  in	the  /usr/lib/sabt/etc
       directory.  The	minimum	 contents  are	as  follows: TDRIVE="tape0_d1"
       #Tape  drive  used  RESTORE_TYPE="no"	  #Restore  type   yes=DEFAULT
       no=ADVANCED SPART="b"		 #Primary Swap drive partition

       You  can also create the custom_prerestore file manually, and use it to
       fully automate the recovery procedure. The file can contain the follow‐
       ing  entries:  INTERACTIVE=["yes | no"] - Specifies whether the session
       is to be interactive or not. A yes entry forces an interactive session.
       A  typical  entry  is  as follows: INTERACTIVE="no" TDRIVE="device_spe‐
       cial_file" - Specifies the device special file name of the  tape	 drive
       from which the standalone kernel was booted. A typical entry is as fol‐
       lows: TDRIVE="tape0_d1" RESTORE_TYPE=["yes | no"] -  Specifies  whether
       this  is	 to  be a default (yes) or an advanced restore (no). A typical
       entry is as follows: RESTORE_TYPE="no" SDRIVE="disk_type device name" -
       Specifies  the primary swap disk drive. This entry requires the follow‐
       ing parameters: disk_type - The disk device model, such as HB00931B93 .
       You can obtain this information by using the following command: # hwmgr
       -show component | grep iomap

	      The hardware identifier is shown under the HWID  column  in  the
	      command output. You use this information to determine the device
	      name of a disk.  device name -  The  device  instance,  such  as
	      dsk8.  This  information is part of the device special file name
	      assigned to the disk. You can obtain this information  by	 using
	      the following command: # hwmgr -show scsi
	      VALID							  PATH
	       32:   0	       cymro	  disk	   none	    2	    1	  dsk0

	      In the preceding command output, the entry under the HWID column
	      identifies  the  disk that you chose by using the show component
	      option.  The HWID is 32 in this example.

	      A	 typical  entry	 is  as	 follows:  SDRIVE="HB00931B93	dsk13"
	      SPART="partition_id"  -  Specifies the primary swap partition on
	      the restored disk.  A typical entry  is  as  follows:  SPART="b"
	      DDRIVE_1="disk_type  device name" - Specifies the root file sys‐
	      tem disk drive. A typical entry is as follows:  DDRIVE_1="RZ1CB-
	      CS  dsk13" PPART_1="partition_id" - Specifies the root file sys‐
	      tem  partition.  A  typical  entry  is  as  follows:   PPART="a"
	      DDRIVE_2="disk_type device name" - Specifies the disk drive used
	      for the /usr  file  system.  A  typical  entry  is  as  follows:
	      DDRIVE_2="HB00931B93  dsk11"  PPART_1="partition_id" - Specifies
	      the /usr file system partition.  A typical entry is as  follows:
	      PPART="g"	 DDRIVE_N="disk_type  device name" Specifies the disks
	      used for each additional file system that is restored,  where  N
	      is an integer ranging from 3 to the total number of file systems
	      to  be  restored.	 Use  entries  similar	 to   the   following:
	      DDRIVE_3="HB00931B93  dsk12"  PPART_N="partition_id  " Specifies
	      the partitions used for each  additional	file  system  that  is
	      restored, where N is an integer ranging from 3 to the total num‐
	      ber of file systems to be restored. Use entries similar  to  the
	      following: PPART_3="c"

       To insert comments in the custom prerestore file, preceded each comment
       line with the number symbol (#).

       Success.	 An error occurred.

       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

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


List of man pages available for DigitalUNIX

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
Vote for polarhome
Free Shell Accounts :: the biggest list on the net