emergency_disk(1M)
emergency_disk --
create emergency recovery boot media
Synopsis
emergency_disk
[-d work_directory]
[-i image_directory]
[-m media]
[-s cd_speed]
[device]
Description
The emergency_disk command creates emergency recovery boot
media customized for your system.
The emergency recovery boot media is used together with:
to restore your system in the event of a system failure.
Typically, after the initial installation of the operating system
and all applications, the emergency recovery boot media and emergency
recovery tape(s) should be created using the emergency_disk and
emergency_rec(1M)
commands.
Then, regular system backups must be performed to copy user and application
data to backup media.
You can use commands such as cpio, tar, gzip,
etc., to create backup media, or use one of the many third-party backup and
restore applications available.
Store all media in a safe and easily accessible location
in case an emergency such as the following occurs:
-
Your system will not boot.
-
System files are corrupted beyond repair.
-
Your hard disk is damaged and has been reformatted or replaced.
In such cases you can use the emergency recovery boot media to bring
your system back up, restore it from the emergency tapes, and then
apply additional backup media to completely restore the system to
the state reflected in the most recent backup media.
Options
-d-
identifies a working directory for temporary files.
The working directory must contain at least 30 MB of free space.
The default is /usr.
Note that emergency_disk will execute faster if /tmp
is used, but be sure that enough free space exists in /tmp
before specifying it.
-i-
places ISO or diskette images in image_directory and does not write
them to media.
For diskette media,
the files are named drf.image.1 and drf.image.2.
These images can later be written to two diskettes using the
dd(1)
command, as in this example:
# cd image_directory
[insert first blank diskette]
# format /dev/rfd0135ds18
# dd if=drf.image.1 of=/dev/rfd0135ds18 bs=32b
[insert second blank diskette]
# format /dev/rfd0135ds18
# dd if=drf.image.2 of=/dev/rfd0135ds18 bs=32b
If a cdrom media type is specified, a CD image named
drf.image.iso is written, that can later be used to write
a CD, as in this example:
# cd image_directory
[insert CD-R/RW media]
# cdrecord -v -dao dev=1,0,0 -data drf.image.iso
The dev=scsibus,target,lun
argument can be determined by executing cdrecord -scanbus.
cdrecord -inq dev=x,y,z can be used to verify that a
particular drive is seen as a CD-RW (versus a CD-ROM) device.
See the
cdrecord(1)
man page for information on additional arguments like speed, driveropts,
how to blank a previously written CD-RW disk, the defaults
file /etc/default/cdrecord, and other details.
By default these images are written to /tmp before being
written to diskette.
-m-
Indicates the media type.
Must be one of diskette or cdrom.
This option is not needed if the device is specified.
If the media type is cdrom and the -i option is not
specified, emergency_disk will master and burn the CD-R or CD-RW
disk if mkisofs and cdrecord are installed (from
the cdrtools package).
If a previously written CD-RW disk is used, emergency_disk will
automatically blank the CD-RW disk before burning.
-s-
Indicates the CD-R/RW media speed for cdrecord.
If this option is not specified cdrecord will use CDR_SPEED in
/etc/default/cdrecord or its internal default value.
Parameters
device-
Identifies the diskette or cdrom drive (e.g. diskette1 or
cdrom1) that will be used to create the emergency recovery boot
media.
The default for floppy media is diskette1.
The default for cdrom media is cdrom1.
For cdrom media the cdrecord dev argument is internally
set by emergency_disk based on this device rather than CDR_DEVICE
in /etc/default/cdrecord.
Note that the cdrtools package must be installed in order to create
an emergency recovery boot CD on a writable CD drive.
The CD-R or CD-RW drive must also be supported by the cdrtools
package.
For more information on cdrtools, see the cdrecord(1) and
mkisofs(8) manual pages.
Usage
To use the emergency boot media,
insert the emergency recovery CD or the first emergency recovery
floppy diskette into the drive, and reboot your system.
If you use diskettes, you'll be prompted to
remove the first diskette and insert the second diskette.
Once the recovery program is started, you'll be presented
with a menu of options:
Emergency Recovery Menu
Mount File Systems
Unmount File Systems
Access UnixWare Shell
Write Master Boot Record
Restore Disk(s)
Reboot
Mount/Unmount File Systems-
Depending on how severely your system is damaged,
you may be able to mount and unmount file systems from your hard disk.
If you can mount the root filesystem, you'll be able to use all
the standard UnixWare utilities to examine the accessible disks.
Access UnixWare Shell-
If you can mount file systems, you can attempt to repair any system
damage you find by launching a shell.
Even if the root disk is unavailable, some commands are provided on
the emergency boot media:
cat(1),
chroot(1M),
cpio(1),
date(1),
dd(1M),
echo(1),
edvtoc(1M),
fdisk(1M),
find(1),
fsck(1M),
grep(1),
ksh(1),
labelit(1M),
ln(1),
ls(1),
mkdir(1),
mkfs(1M),
mount(1M),
prtvtoc(1M),
rm(1),
stty(1),
and
vi(1).
Write Master Boot Record-
This option writes the UnixWare Master Boot Record to the boot sector of
the primary hard disk.
This option is useful if the disk is known to have a valid
operating system on it, yet the error "No OS found", "No operating system",
or a similar message is displayed when you attempt to boot from the disk.
Note that any other OS boot loader in the boot sector (such as
grub, lilo, or System Commander) will be overwritten
by this option.
Restore Disks-
Use this option to restore the primary and secondary hard disks from
tape media created with the
emergency_rec(1M)
command.
If you select this option:
-
The UNIX partition on the primary hard disk that contains UnixWare is
restored.
If the primary hard disk contains a system partition,
then this partition is also restored.
If the /home,
/home2, and /var
file systems were on the secondary hard disk,
then these file systems are restored to the secondary hard disk.
-
If the -e option was specified when running
emergency_rec,
then the entire primary hard disk is restored.
This includes all partitions on the primary hard disk and not just the
UnixWare and system partitions.
The emergency recovery media can be used only on the system on which
emergency_disk was run to create them.
NOTE:
If you are using encapsulated or mirrored disks, the emergency
recovery procedure for such disks is documented in the section
``Emergency recovery with an encapsulated or mirrored root disk'' in the UnixWare 7 System Handbook.
Examples
To create an emergency recovery boot CDROM using a 40X CD-RW drive
and the faster, /tmp work directory:
emergency_disk -d /tmp -s 40 cdrom1
To create emergency recovery boot floppies:
emergency_disk -d /tmp
Warnings
Attempting to use the emergency media to copy UnixWare between
systems is prohibited.
The emergency media is customized for the system on which it
is created and may have unpredictable ramifications if used on another
system.
Files
A temporary log file is created in
/tmp/drf_PID.log,
where PID is the process ID for the emergency_disk command.
If an error is encountered a message is displayed to standard error and
additional information is provided in this log file.
Exit codes
The emergency_disk command exits with one of the following values:
0-
Success
1-
Failure.
See the /tmp/drf_PID.log log file.
Diagnostics
A temporary log file is created in
/tmp/drf_PID.log,
where PID is the process ID for the emergency_disk command.
If an error is encountered a message is displayed to standard error and
additional information is provided in this log file.
References
emergency_rec(1M),
``Emergency recovery with an encapsulated or mirrored root disk'' in the UnixWare 7 System Handbook
Notices
If you change the hard disk configuration on your system (for example,
you add or replace a hard disk), you must create new emergency
recovery media to ensure that they match your current system
configuration.
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004