mkfdmn(8) System Manager's Manual mkfdmn(8)
NAME
mkfdmn - Creates a new AdvFS file domain
SYNOPSIS
/sbin/mkfdmn [-F] [-l num_pages] [-o] [-p num_pages] [-r] [-x num_pages] [-V3 | -V4] special domain
OPTIONS
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. Overwrites an existing file domain, allowing you to recreate the domain structure. 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. Specifies the
file 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, create an AdvFS file domain that uses the on-disk formats
employed by AdvFS prior to the release of Version 5.0 that is, domain version number (DVN) of 3. If you specify -V4, create an AdvFS file
domain that uses the on-disk formats employed by AdvFS starting with the release of Version 5.0 that is, DVN of 4. If neither option is
specified, the default action is to use the Version 5.0 on-disk formats for the file 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.
OPERANDS
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
file domain. Specifies the name of the file domain.
DESCRIPTION
The mkfdmn command creates a file domain, which is a logical construct containing both physical volumes (disks or disk partitions) and
filesets. When you create a file domain, you must specify one volume. This can be an LSM volume.
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 whose partitions would overlap any volumes used by another file system (as indicated on the disk label), includ-
ing 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.
Caution
Existing data on the volume you assign to a new file domain is destroyed when the file 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 file domain must contain
one or more filesets.
After you run the mkfdmn command, you must run the mkfset command to create at least one fileset within the new file domain. You can access
the file domain as soon as you mount one or more filesets. For more information about creating filesets, see mkfset(8).
To remove a file domain, dismount all filesets in the domain you want to remove. Then use the rmfdmn command to remove the file domain.
Using the rmfdmn command is preferable to removing the directory defining a file domain because the command changes the disk label informa-
tion to indicate that the partition is no longer in use by AdvFS.
If the /etc/fdmns directory is lost or the volumes of a file domain are moved to a different system, you can use the advscan command to re-
create a file domain. See advscan(8).
File 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 additional 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 preallo-
cate 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 file domains with the -V3 option. If your estimated number 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 Pages BMT Preallocation Size
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
----------------------------------------------------------------------
NOTES
If you make a file domain using the -p or -x options to increase 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 parameter):
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.
RESTRICTIONS
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 file domain names.
ERRORS
Command execution continues after the following warnings are displayed: mkfdmn: Invalid value for -x mkfdmn: Setting to minimum value of
128
Explanation:
You have entered an invalid value for the -x option.
mkfdmn: Invalid value for -p mkfdmn: Setting to minimum value of 0.
Explanation:
You have entered an invalid value for the -p option.
EXAMPLES
The following example creates the accounts_dmn file domain with the special device /dev/disk/dsk1c as the initial volume: # mkfdmn
/dev/disk/dsk1c accounts_dmn
Until you create and mount a fileset for the accounts_dmn file domain, you cannot access the file system.
FILES
Contains file domain names and devices.
SEE ALSO
Commands: addvol(8), advscan(8), mkfset(8), mount(8), rmfdmn(8), showfdmn(8)
Files: fdmns(4)
mkfdmn(8)