This command is used to do the following:
- o
- Create and modify an fdisk partition table on x86 systems
- o
- Create and modify an fdisk partition table on removable media on
SPARC or x86 systems
- o
- Install the master boot record that is put in the first sector of the
fixed disk on x86 systems only
This table is used by the first-stage bootstrap (or firmware) to
identify parts of the disk reserved for different operating systems, and to
identify the partition containing the second-stage bootstrap (the
active Solaris partition). The rdevice argument must be used
to specify the raw device associated with the fixed disk, for example,
/dev/rdsk/c0t0d0p0.
The program can operate in three different modes. The first is
interactive mode. In interactive mode, the program displays the partition
table as it exists on the disk, and then presents a menu allowing the user
to modify the table. The menu, questions, warnings, and error messages are
intended to be self-explanatory.
In interactive mode, if there is no partition table on the disk,
the user is given the options of creating a default partitioning or
specifying the initial table values. The default partitioning allocates the
entire disk for the Solaris system and makes the Solaris system partition
active. In either case, when the initial table is created, fdisk also
writes out the first-stage bootstrap (x86 only) code along with the
partition table. In this mode, (x86 only) when creating an entry for a
non-EFI partition on a disk that is larger than 2 TB (terabytes),
fdisk warns that the maximum size of the partition is 2 TB. Under
these conditions percentages displayed by fdisk are based on 2
TB.
The second mode of operation is used for automated entry addition,
entry deletion, or replacement of the entire fdisk table. This mode
can add or delete an entry described on the command line. In this mode the
entire fdisk table can be read in from a file replacing the original
table. fdisk can also be used to create this file. There is a command
line option that will cause fdisk to replace any fdisk table
with the default of the whole disk for the Solaris system.
The third mode of operation is used for disk diagnostics. In this
mode, a section of the disk can be filled with a user-specified pattern and
mode sections of the disk can also be read or written.
Note -
The third mode of operation is not currently supported
for extended partitions
When fdisk creates a partition, the space is allocated in
the fdisk partition table, but the allocated disk space is not
initialized. newfs(8) is required to create and write file system
metadata to the new partition, and format(8) is required to write the
VTOC or EFI/GPT metadata.
The menu options for interactive mode given by the fdisk
program are:
Create a partition
This option allows the user to create a new partition.
The maximum number of partitions is 4. The program will ask for the type of
the partition (SOLARIS, MS-DOS, UNIX, or other). It will then ask for the size
of the partition as a percentage of the disk. The user may also enter the
letter c at this point, in which case the program will ask for the
starting cylinder number and size of the partition in cylinders. If a c
is not entered, the program will determine the starting cylinder number where
the partition will fit. In either case, if the partition would overlap an
existing partition or will not fit, a message is displayed and the program
returns to the original menu.
Change Active (Boot from) partition
This option allows the user to specify the partition
where the first-stage bootstrap will look for the second-stage bootstrap,
otherwise known as the active partition.
Delete a partition
This option allows the user to delete a previously
created partition. Note that this will destroy all data in that
partition.
Change between Solaris and Solaris2 Partition
IDs
This option allows the user to switch between the current
fdisk operating system partition identifier and the previous one. This
does not affect any data in the disk partition and is provided for
compatibility with older software.
Edit/View extended partitions
This option provides the extended partition menu to the
user. Use the extended partition menu to add and delete logical drives, change
the sysid of the logical drives, and display logical drive information. To
commit the changes made in the extended partition, you must return to the main
menu using the extended partition submenu option
r. There is also an
option to display the list of options that the extended partition submenu
supports. Given below is the list:
a
Add a logical drive.
Use this submenu option to add a logical drive. There are three
pieces of information that are required: The beginning cylinder, the size
(in cylinders or in human readable form - KB, MB, or GB), and the partition
ID. While specifying the partition ID, there is an option (I) that
you can use to list the supported partitions.
d
Delete a logical drive.
Use this submenu option to delete a logical drive. The only input
required is the number of the logical drive that is to be deleted.
h
Display the help menu.
This submenu option displays the supported operations in the
extended partition submenu.
i
Change the id of the logical drive.
Use this submenu option to change the system ID of the existing
logical drives. A list of supported system IDs is displayed when you use the
I option when in this submenu.
p
Display the logical drive layout.
Displays the logical drive information to stdout. This output
reflects any changes made during the current run of the fdisk
program. The changes are not committed to the disk until return to the main
menu (using the submenu r) and choose the option to commit the
changes to the disk.
r
Return to the main
fdisk menu.
Exit the extended partition submenu and return to the main
menu.
Use the following options to include your modifications to the
partition table at this time or to cancel the session without modifying the
table:
Exit
This option writes the new version of the table created
during this session with fdisk out to the fixed disk, and exits the
program.
Cancel
This option exits without modifying the partition
table.
The following options apply to fdisk:
-A
id:act:bhead:bsect:bcyl:ehead:esect:ecyl:rsect:numsect
Add a partition as described by the argument (see the
-F option below for the format). Use of this option will zero out the
VTOC on the Solaris partition if the fdisk table changes.
-b master_boot
Specify the file master_boot as the master boot
program. The default master boot program is /boot/pmbr.
-B
Default to one Solaris partition that uses the whole
disk. On an x86 machine, if the disk is larger than 2 TB (terabytes), the
default size of the Solaris partition will be limited to 2 TB.
-d
Turn on verbose debug mode. This will cause
fdisk to print its state on stderr as it is used. The output from this
option should not be used with -F.
-D
id:act:bhead:bsect:bcyl:ehead:esect:ecyl:rsect:numsect
Delete a partition as described by the argument (see the
-F option below for the format). Note that the argument must be an
exact match or the entry will not be deleted! Use of this option will zero out
the VTOC on the Solaris partition if the fdisk table
changes.
-E [slot:active]
Create an
EFI partition that uses the entire disk.
By default this partition entry will be placed into the first slot
within the partition table and will not be marked active. The remaining
slots within the table will be zeroed out.
Some broken firmware implementations have issues booting in
CSM/Legacy/BIOS mode from EFI partitions that are not set active. Others
have issues with booting from EFI partitions without UEFI if the protective
partition table entry is in the first slot. To work around these problems,
the -E option takes an optional argument which can be used to
override the defaults described above.
slot
Specify the MBR slot into which the EFI partition should
be placed. This accepts a value in the range 0 to 3 with the default being
0.
active
Specify whether the EFI partition entry should be marked
active; 0 specifies not active (the default) and 1 means
active.
-F fdisk_file
Use fdisk file
fdisk_file to initialize table. Use
of this option will zero out the
VTOC on the Solaris partition if the
fdisk table changes.
The fdisk_file contains four specification lines for the
primary partitions followed by specification lines for the logical drives.
You must have four lines for the primary partitions if there is at least one
logical drive. In this case, if the number of primary partitions to be
configured is less than four, the remaining lines should be filled with
zeros.
Each line is composed of entries that are position-dependent, are
separated by whitespace or colons, and have the following format:
id act bhead bsect bcyl ehead esect ecyl rsect numsect
...where the entries have the following values:
id
This is the type of partition and the correct numeric
values may be found in fdisk.h.
act
This is the active partition flag; 0 means not
active and 128 means active. For logical drives, this flag will always
be set to 0 even if specified as 128 by the user.
bhead
This is the head where the partition starts. If this is
set to 0, fdisk will correctly fill this in from other
information.
bsect
This is the sector where the partition starts. If this is
set to 0, fdisk will correctly fill this in from other
information.
bcyl
This is the cylinder where the partition starts. If this
is set to 0, fdisk will correctly fill this in from other
information.
ehead
This is the head where the partition ends. If this is set
to 0, fdisk will correctly fill this in from other
information.
esect
This is the sector where the partition ends. If this is
set to 0, fdisk will correctly fill this in from other
information.
ecyl
This is the cylinder where the partition ends. If this is
set to 0, fdisk will correctly fill this in from other
information.
rsect
The relative sector from the beginning of the disk where
the partition starts. This must be specified and can be used by fdisk
to fill in other fields. For logical drives, you must make sure that there are
at least 63 free sectors before the rsect specified for a logical
drive.
numsect
The size in sectors of this disk partition. This must be
specified and can be used by fdisk to fill in other fields.
-g
Get the label geometry for disk and display on stdout
(see the -S option for the format).
-G
Get the physical geometry for disk and display on stdout
(see the -S option for the format).
-h
Issue verbose message; message will list all options and
supply an explanation for each.
-I
Forgo device checks. This is used to generate a file
image of what would go on a disk without using the device. Note that you must
use -S with this option (see above).
-n
Don't update fdisk table unless explicitly
specified by another option. If no other options are used, -n will only
write the master boot record to the disk. In addition, note that fdisk
will not come up in interactive mode if the -n option is
specified.
-o offset
Block offset from start of disk. This option is used for
-P, -r, and -w. Zero is assumed when this option is not
used.
-P fill_patt
Fill disk with pattern fill_patt. fill_patt
can be decimal or hex and is used as number for constant long word pattern. If
fill_patt is #, then pattern is block # for each block. Pattern
is put in each block as long words and fills each block (see -o and
-s).
-r
Read from disk and write to stdout. See -o and
-s, which specify the starting point and size of the operation.
-R
Treat disk as read-only. This is for testing
purposes.
-s size
Number of blocks to perform operation on (see
-o).
-S geom_file
Set the label geometry to the content of the
geom_file. The
geom_file contains one specification line. Each
line is delimited by a new-line character (
\n). If the first character
of a line is an asterisk (*), the line is treated as a comment. Each line is
composed of entries that are position-dependent, are separated by white space,
and have the following format:
pcyl ncyl acyl bcyl nheads nsectors sectsiz
where the entries have the following values:
pcyl
This is the number of physical cylinders for the
drive.
ncyl
This is the number of usable cylinders for the
drive.
acyl
This is the number of alt cylinders for the drive.
bcyl
This is the number of offset cylinders for the drive
(should be zero).
nheads
The number of heads for this drive.
nsectors
The number of sectors per track.
sectsiz
The size in bytes of a sector.
-t
Adjust incorrect slice table entries so that they will
not cross partition table boundaries.
-T
Remove incorrect slice table entries that span partition
table boundaries.
-v
Output the HBA (virtual) geometry dimensions. This option
must be used in conjunction with the -W flag. This option will work for
platforms which support virtual geometry. (x86 only)
-w
Write to disk and read from stdin. See -o and
-s, which specify the starting point and size of the operation.
-W −
Output the disk table to stdout.
-W fdisk_file
Create an fdisk file fdisk_file from disk
table. This can be used with the -F option below.
Most messages will be self-explanatory. The following may appear
immediately after starting the program:
Fdisk: cannot open <device>
This indicates that the device name argument is not
valid.
Fdisk: unable to get device parameters for
device <device>
This indicates a problem with the configuration of the
fixed disk, or an error in the fixed disk driver.
Fdisk: error reading partition table
This indicates that some error occurred when trying
initially to read the fixed disk. This could be a problem with the fixed disk
controller or driver, or with the configuration of the fixed disk.
Fdisk: error writing boot record
This indicates that some error occurred when trying to
write the new partition table out to the fixed disk. This could be a problem
with the fixed disk controller, the disk itself, the driver, or the
configuration of the fixed disk.