sammkfs, samfsinfo - Constructs or displays information for
a Sun QFS or SAM-QFS file system
/opt/SUNWsamfs/sbin/sammkfs [-a allocation_unit] [-i inodes]
[-A] [-P] [-S] [-V] fs_name
The sammkfs command creates a Sun QFS or SAM-QFS file system
from the disk partitions that belong to the family set
fs_name, where fs_name is the family set name as defined in
the mcf file. Up to 252 disk partitions can be specified in
the mcf file for a Sun QFS or SAM-QFS file system. The
sammkfs command can also be used to recreate a file system
after a disaster.
The sammkfs command can create either a version 2 file
system that is backwards compatible with previous releases,
or a version 2A file system that has new features, but is
not compatible with previous releases. By default, a
version 2A file system is created. See -P parameter below
for details on the new features, and how to create a version
2 file system.
The sammkfs command aligns the block allocation bit maps and
round robins them on the metadata devices for improved
performance. This behavior is backwards compatible with
previous releases. The option feature Aligned Maps is set.
The samfsinfo command displays the structure of an existing
Sun QFS or SAM-QFS file system. The output is similar to
that obtained by using the -V option to the sammkfs command.
These commands accept the following options:
Specifies the disk allocation unit (DAU). The DAU
is the basic unit of online storage. When you
specify a DAU size, you specify the number of
1024-byte (1 kilobyte) blocks to be allocated for
The DAU size you can specify depends on the type
of file system being initialized, as follows:
o The SAM-QFS file system is an ms file system.
The disk devices in it are all md devices.
Both data and metadata are written to the md
devices. The allocation_unit specifies the DAU
to be used for the md devices. Possible
allocation_unit specifications are 16, 32, or
64 (the default).
o The Sun QFS or SAM-QFS file systems are ma file
systems. The metadata in these file systems is
written to mm devices. The disk devices in
these file systems are specified as either md,
mr, or gXXX devices, as follows:
- For the md devices, possible allocation_unit
specifications are 16, 32, or 64 (the
default). A single file system cannot have
md devices mixed among the mr and gXXX
- For mr devices, the DAU is fully adjustable.
Specify an allocation_unit that is a
multiple of 8 in the following range for mr
devices: 8 < allocation_unit < 65528. The
default is 64.
- For gXXX devices, which specify striped
groups, the DAU is fully adjustable. If the
file system contains striped groups, the
minimum unit of disk space allocated is the
DAU multiplied by the number of members in
the striped group. Specify an
allocation_unit that is a multiple of 8 in
the following range for gXXX devices:
8 < allocation_unit < 65528. The default is
You can mix mr and gXXX devices in a single Sun
QFS or SAM-QFS file system. If these device
types are mixed, the allocation_unit specified
is used for both device types. If no
allocation_unit is specified, the DAU size used
for each type of device is 256.
-i inodes Specifies the number of inodes to be allocated for
this file system. This is the total number of
user inodes that can be used for the life of this
file system. In Sun QFS and SAM-QFS version 2
superblock file systems, a number of inodes are
reserved for file system usage, and are
unavailable to the user. This number is in
addition to the specified number of user inodes.
The actual number of inodes available vary from
that specified, due to rounding to metadata DAU
NOTE: By specifying this option, you eliminate
the possibility of ever increasing the number of
inodes for the file system. Therefore, Sun does
not recommend the use of this option.
When this option is specified, later use of the
samgrowfs(1M) command increases the size of the
file system, but it cannot increase the number of
allowable inodes. For more information on
enlarging file systems, see the WARNINGS section
of this man page and the samgrowfs(1M) man page.
-A Uses NFSv4 ACL style for the filesystem ACLs
instead of POSIX ACL style. This feature is
available only in releases of Solaris beyond
-P Specifies that a previous version of the file
system be created. This version creates a version
2 superblock and is compatible with SAM-QFS
version 4.6. This version cannot use the
following features however: large host table,
extended attributes, and online grow. Without the
-P parameter, a version 2A superblock is created,
the above features are available, and the file
system is not usable with SAM-QFS version 4.6 or
-S Indicates that this file system is shared. In
order to mount the file system as a Sun QFS shared
file system, you must also create a hosts.fs_name
configuration file. For more information on this
configuration file and other aspects of the Sun
QFS shared file system, see the Sun QFS File
System Configuration and Administration Guide.
For information on configuring a hosts file, see
the hosts.fs(4) man page.
-V Writes configuration information to standard
output but does not execute the sammkfs command.
This information can be used to create a new file
The samfsinfo command should be used to generate
configuration information for an existing file
Example 1. The following command creates SAM-QFS file
system with a DAU size of 128 kilobytes:
server# sammkfs -a 128 samfs1
/etc/opt/SUNWsamfs/mcf The configuration file for a Sun
QFS or SAM-QFS file system
As with creating any type of file system, if you specify the
wrong partition names, you risk damaging user or system
data. Be sure to specify partitions that are otherwise
unused on your system. Do not use overlapping partitions.
With SAM-QFS 4.1 and greater AND Solaris 64bit kernels which
support large disk devices (greater than 1 TB), it is
possible to have partitions that are greater than 1 TB. Note
that these file systems are not usable on Solaris systems
that do not support large disk devices.
dd(1M), samd(1M), samgrowfs(1M), undamage(1M).
Sun QFS File System Configuration and Administration Guide.
Sun Storage Archive Manager Configuration and Administration
Be careful when using the -i inodes option for this command.
By using this option, you dictate the maximum number of
inodes allowed for the life of this file system. This
eliminates the possibility of ever using the samgrowfs(1M)
command to increase the number of files in this file system.
After a file system is made with -i specified, the
samgrowfs(1M) command can only be used to increase the size
of the file system in terms of bytes.
Data alignment refers to matching the allocation unit of the
RAID controller with the allocation_unit of the file system.
A mismatched alignment causes a read-modify-write operation
for I/O that is less than the block size. The optimal
alignment formula is as follows:
allocation_unit = RAID_stripe_width * number_of_data_disks
For example, if a RAID-5 unit has a total of 8 disks with 1
of the 8 being the parity disk, the number of data disks is
7. If the RAID stripe width is 64 kilobytes, then the
optimal allocation_unit is 64 * 7 = 448.