mkfdmn(8)mkfdmn(8)NAMEmkfdmn - Creates a new AdvFS domain
/sbin/mkfdmn [-F] [-l num_pages] [-o] [-p num_pages] [-r] [-x
num_pages] [-V3 | -V4] special domain
Ignores overlapping partition or block warnings. Sets the number of
pages in the log file. AdvFS rounds this number up to a multiple of
four. Allows reuse of an existing domain name. It destroys the exist‐
ing domain and creates a new domain with the existing domain name.
Sets the number of pages to preallocate for the bitfile metadata table
(BMT). The default is 0 (zero) pages. This option may be useful if you
have chosen the -V3 option; it is not applicable for domains created
with V4. Specifies the domain as the local root domain. This prevents
multiple volumes in the root domain. AdvFS supports only one volume in
the local root domain. This does not apply to the cluster root domain.
If you specify -V3, creates an AdvFS domain that uses the on-disk for‐
mats employed by AdvFS prior to the release of OS Version 5.0; that is,
creates a domain with a domain version number (DVN) of 3. If you spec‐
ify -V4, creates an AdvFS domain that uses the on-disk formats employed
by AdvFS starting with the release of OS Version 5.0; that is, creates
a domain with a DVN of 4. If neither option is specified, the default
action is to use the DVN 4 on-disk formats for the domain. Sets the
number of pages by which the BMT extent size grows. The value must be
greater than or equal to 128 pages. The default is 128 pages. This
option may be useful if you have chosen the -V3 option; it is not
applicable for domains created with the -V4 option
Specifies the block special device name, such as /dev/disk/dsk1c, or
the LSM volume name of the initial volume that you use to create the
domain. This command supports short hand names for block special
devices. For example, if you enter dsk2g, it will be translated to
/dev/disk/dsk2g. Specifies the name of the domain.
The mkfdmn command creates a domain, which is a logical construct con‐
taining both physical volumes (disks or disk partitions) and filesets.
When you create a domain, you must specify one volume. This can be an
The minimum size of an AdvFS domain depends, to some degree, on the
size of the disk or logical volume on which it is created. It is gener‐
ally not possible to create a domain smaller than 6 or 7 megabytes. If
you attempt to create a domain on a disk or logical volume that is too
small, AdvFS will display errors like the following: bs_disk_init: disk
is too small mkfdmn: domain init error ENO_MORE_BLKS (-1040) mkfdmn:
can't create new domain 'small_domain'
If you try to add a volume with partitions that overlap any volumes
used by another file system (as indicated on the disk label), including
UFS, AdvFS, and LSM, the mkfdmn command displays a message asking if
you want to continue: Partition(s) which overlap /dev/rdisk/dsk10a are
marked in use. If you continue with the operation you can possibly
destroy existing data. CONTINUE? [y/n] y
Use the -F option to disable testing for overlap.
If you are creating a domain and requesting a partition that overlaps
an existing /etc/fdmns entry, the mkfdmn command will not create the
partition. If the partition is in use, you will receive a message ask‐
ing if you want to override. If you want to override without a prompt,
use the -F option.
Existing data on the volume you assign to a new domain is destroyed
when the domain is created.
The mkfdmn command does not create a file system that you can mount.
In order to mount an AdvFS file system, the domain must contain one or
more filesets. Run the mkfset command to create at least one fileset
within the new domain. You can access the domain as soon as you mount
one or more filesets. For more information about creating filesets, see
To remove a domain, dismount all filesets in the domain you want to
remove. Then use the rmfdmn command to remove the domain. Using the
rmfdmn command is preferable to removing the directory defining a
domain because the command changes the disk label information to indi‐
cate that the partition is no longer in use by AdvFS.
If the /etc/fdmns directory is lost or the volumes of a domain are
moved to a different system, you can use the advscan command to re-cre‐
ate a domain. See advscan(8).
Domains created with the -V3 option that contain a very large number of
files may need added BMT mcells (similar to inodes in UFS). By
default, AdvFS attempts to grow the BMT by 128 pages each time addi‐
tional mcells are needed. This may cause the metadata storage to become
very fragmented, resulting in a premature “out of disk space” error.
You can reduce the amount of BMT metadata fragmentation for file
domains created with the -V3 option either by preallocating space for
the BMT or by increasing the number of pages that the system attempts
to grow the BMT each time space is needed. Use the -p option to preal‐
locate all the BMT space you expect the file domain to need. Note that
space that is preallocated cannot be deallocated. Use the -x option to
specify how many pages the BMT should be extended each time additional
mcells are needed.
The following table provides guidelines for BMT growth size in pages
(-x option) and BMT preallocation (-p option) that you may want to use
if you are creating domains with the -V3 option. If your estimated num‐
ber of files is greater than those listed in the table, keep doubling
the last table entry until you get a value that is close to your needs.
Number of Files BMT Growth Size in BMT Preallocation Size
Pages in Pages
Less than 50,000 Default (128) 3,600
100,000 256 7,200
200,000 512 14,400
300,000 768 21,600
400,000 1024 28,800
800,000 2048 57,600
If you have domains created on systems prior to Version 5 or domains
created with the V3 option of mkfdmn, use the -p or -x option to grow
the BMT extent allocations. You must use the same option with the same
number of pages when you add a volume to the file domain with the
addvol command. See addvol(8) for information about adding a volume to
a file domain.
Use a value in the -x num_pages argument that maintains the following
relationship between the BMT extent size (the number of pages for the
-x parameter) and the log file size (the number of pages for the -l
BMT extent size <= (log file size * 8184) / 4
It takes about one minute to process 5000 BMT extent size pages with
the -x option. A process that initiates a BMT extent size operation
must take into account that very large values for -x will take a long
time to complete.
This command supports shorthand names for LSM volume names. For exam‐
ple, if you enter the following: # mkfdmn testdg.vol1 dom1
the volume name will be translated to: # mkfdmn /dev/vol/testdg/vol1
You must be the root user to use this command.
All white space characters (tab, line feed, space, and so on) and the /
# : * ? characters are invalid for domain names.
Command execution continues after the following warnings are displayed:
mkfdmn: Invalid value for -x mkfdmn: Setting to minimum value of 128
You have entered an invalid value for the -x option. mkfdmn:
Invalid value for -p mkfdmn: Setting to minimum value of 0.
You have entered an invalid value for the -p option.
The following example creates the accounts_dmn domain with the special
device /dev/disk/dsk1c as the initial volume: # mkfdmn /dev/disk/dsk1c
Until you create and mount a fileset for the accounts_dmn domain, you
cannot access the file system.
Contains domain names and devices.
Commands: addvol(8), advscan(8), mkfset(8), mount(8), rmfdmn(8),