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  man pages->Tru64 Unix man pages -> btextract (8)              



NAME    [Toc]    [Back]

       btextract - Extracts the file systems from tape in singleuser
 mode in memory

SYNOPSIS    [Toc]    [Back]


DESCRIPTION    [Toc]    [Back]

       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 customized 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 btcreate
 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

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

       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

       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    [Toc]    [Back]
       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  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/custom_install.sh   script  during  the
       btcreate session, the btextract command invokes  the  custom_install.sh
  script  before  exiting.  See btcreate for
       more information.

       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    [Toc]    [Back]
       When  you boot a system using bootable tape, the btextract
       command prompts you to create an answer file that provides
       the  minimum  information  needed to complete the boot and
       restore operation. This custom_prerestore file is  a  text
       file located in the /usr/lib/sabt/etc directory. The minimum
        contents        are         as         follows:
       TAPE_USED="/dev/tape/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 following 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"
       TAPE_USED="device_special_file"  -  Specifies  the  device
       special  file  name of the tape drive from which the standalone
 kernel was booted. A typical entry is  as  follows:
       TDRIVE="/dev/tape/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 following 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
                    SCSI               DEVICE  DEVICE  DRIVER NUM
    OWNER     PATH    FILE       VALID     PATH
               32:  0        cymro     disk    none     2       1
              dsk0   [0/0/0]

              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 system  disk
              drive.    A    typical   entry   is   as   follows:
              DDRIVE_1="RZ1CB-CS dsk13" PPART_1="partition_id"  -
              Specifies the root file system 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 number  of  filesystems
              to  be restored. Use entries similar to the following:

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

RETURN VALUES    [Toc]    [Back]

       Success.  An error occurred.

FILES    [Toc]    [Back]

       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    [Toc]    [Back]

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

[ Back ]
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