Commands Reference, Volume 1

crfs Command

Purpose

Adds a file system.

Syntax

crfs -v VfsType { -g VolumeGroup | -d Device } [ -l LogPartitions ] -m MountPoint [ -n NodeName ] [ -u MountGroup ] [ -A { yes | no } ] [ -p {ro | rw } ] [ -a Attribute= Value ... ] [ -t { yes | no } ]

Description

The crfs command creates a file system on a logical volume within a previously created volume group. A new logical volume is created for the file system unless the name of an existing logical volume is specified using the -d. An entry for the file system is put into the /etc/filesystems file.

Note

The file system is created with the setgid (set group ID) bit enabled. This determines the default group permissions. All directories created under the new file system will have the same default group permissions.

You can use the File Systems application in Web-based System Manager (wsm) to change file system characteristics. You could also use the System Management Interface Tool (SMIT) smit crfs fast path to run this command.

Flags

-a Attribute=Value	Specifies a virtual file system-dependent attribute/value pair. To specify more than one attribute/value pair, provide multiple -a Attribute=Value parameters (see example). The following attribute/value pairs are specific to the Journaled File System (JFS):
	-a ag={ 8 \| 16 \| 32 \| 64 } Specifies the allocation group size in megabytes. An allocation group is a grouping of inodes and disk blocks similar to BSD cylinder groups. The default ag value is 8.
	-a bf={ true \| false } Specifies a large file enabled file system. See "Understanding Large File Enabled File Systems" for more information. If you do not need a large file enabled file system, set this option to false; this is the default. Specifying bf=true requires a fragment size of 4096 and compress=no.
	-a compress={ no \| LZ } Specifies data compression. If you do not want data to be compressed, set this option to no. The default compress value is no. Selecting compression requires a fragment size of 2048 or less.
	-a frag={ 512 \| 1024 \| 2048 \| 4096 } Specifies the JFS fragment size in bytes. A file system fragment is the smallest unit of disk storage that can be allocated to a file. The default fragment size is 4096 bytes.
	-a logname=LVName Specifies the log logical volume name. The specified logical volume will be the logging device for the new JFS. The LVName logical volume must already exist. The default action is to use an existing logging device in the target volume group.
	-a nbpi={ 512 \| 1024 \| 2048 \| 4096 \| 8192 \| 16384 \| 32768 \| 65536 \| 131072 } Specifies the number of bytes per i-node (nbpi). The nbpi affects the total number of i-nodes on the file system. The nbpi value is inversely proportional to the number of i-nodes on the file system. The default nbpi value is 4096 bytes.
	-a size=Value Specifies the size of the Journaled File System. Size can be specified in units of 512-byte blocks, Megabytes or Gigabytes. If Value has the M suffix, it is interpreted to be in Megabytes. If Value has a G suffix, it is interpreted to be in Gigabytes. If the specified size is not evenly divisible by the physical partition size, it is rounded up to the closest number that is evenly divisible. This attribute is required when creating a JFS file system. See "Understanding JFS Size Limitations" for more information.
	The maximum size of a JFS file system is a function of its fragment size and the nbpi value. These values yield the following size restrictions: nbpi Fragment size in bytes Maximum size in Maximum size in Maximum size in 512-byte blocks Megabytes Gigabytes 512 512, 1024, 2048, 4096 16777216 8192 8 1024 512, 1024, 2048, 4096 33554432 16384 16 2048 512, 1024, 2048, 4096 67108864 32768 32 4096 512, 1024, 2048, 4096 134217728 65536 64 8192 512, 1024, 2048, 4096 268435456 131072 128 16384 512 268435456 262144 256 16384 1024, 2048, 4096 536870912 524288 512 32768 512 268435456 1048576 1024 32768 1024 536870912 2097152 2048 32768 2048, 4096 1073741824 4194204 4096 65536, 131072 512 268435456 8388608 8192 65536, 131072 1024 536870912 16777216 16384 65536, 131072 2048 1073741824 33554432 32768 65536, 131072 4096 2147483648 67108804 65536 You can have NBPI values from 512 to 128K, with corresponding maximum file system sizes.
	The volume group in which the file system resides defines a maximum logical volume size and also limits the file system size. Notes: The ag, bf, compress, frag, and nbpi attributes are set at file system creation and cannot be changed after the file system is successfully created. The size attribute defines the minimum file system size, and you cannot decrease it once the file system is created. The root filesystem ( / ) cannot be compressed. Some nbpi values and allocation group sizes are mutually exclusive. See "Understanding JFS Size Limitations" for information.
	The following attribute/value pairs are specific to the Enhanced Journaled File System (JFS2):
	-a agblksize={ 512 \| 1024 \| 2048 \| 4096 } Specifies the JFS2 block size in bytes. A file system block is the smallest unit of disk storage that can be allocated to a file. The default block size is 4096 bytes.
	-a logname=LVName Specifies the log logical volume name. The specified logical volume is the logging device for the new JFS2. The LVName logical volume must already exist. The default action is to use an existing logging device in the target volume group. Keyword INLINE can be used to place the log in the logical volume with the JFS2 file system. The INLINE log defaults to .4% of the logical volume size if logsize is not specified.
	-a logsize=Value Specifies the size for an INLINE log in MBytes. Ignored if INLINE log not being used. Cannot be greater than 10% of the size of the filesystem.
	-a dense Specifies when files are created with holes JFS2 will allocate disk blocks for those holes and fill them with 0's.
	-a size=Value Specifies the size of the JFS2 in 512-byte blocks. If the specified size is not evenly divisible by the physical partition size, it is rounded up to the closest number that is evenly divisible. This attribute is required when creating a JFS2 file system unless the -d flag has been specified. If the -d flag is specified, the file system is the size of the logical volume. The volume group in which the file system resides defines a maximum logical volume size and limits the file system size.
	Note The agblksize and dense attributes are set at file system creation and cannot be changed after the file system is successfully created. The size attribute defines the minimum file system size, and you cannot decrease it once the file system is created.
-A	Specifies whether the file system is mounted at each system restart: yes File system is automatically mounted at system restart. no File system is not mounted at system restart.
-d Device	Specifies the device name of a device or logical volume on which to make the file system. This is used to create a file system on an already existing logical volume.
-g VolumeGroup	Specifies an existing volume group on which to make the file system. A volume group is a collection of one or more physical volumes.
-l LogPartitions	Specifies the size of the log logical volume, expressed as a number of logical partitions. This flag applies only to JFS and JFS2 file systems that do not already have a log device.
-m MountPoint	Specifies the mount point, which is the directory where the file system will be made available. Note If you specify a relative path name, it is converted to an absolute path name before being inserted into the /etc/filesystems file.
-n NodeName	Specifies the remote host name where the file system resides. This flag is only valid with remote virtual file systems such as the Network File System (NFS).
-p	Sets the permissions for the file system. ro Read-only permissions rw Read-write permissions
-t	Specifies whether the file system is to be processed by the accounting subsystem: yes Accounting is enabled on the file system. no Accounting is not enabled on the file system (default value).
-u MountGroup	Specifies the mount group.
-v VfsType	Specifies the virtual file system type.

Security

Access Control: Only the root user can run this command.

Examples

To make a JFS on the rootvg volume group with nondefault fragment size and nondefault nbpi, enter:
```
crfs  -v jfs  -g  rootvg  -m /test -a \ size=32768 -a frag=512 -a nbpi=1024
```
This command creates the /test file system on the rootvg volume group with a fragment size of 512 bytes, a number of bytes per i-node (nbpi) ratio of 1024, and an initial size of 16MB (512 * 32768).
To make a JFS on the rootvg volume group with nondefault fragment size and nondefault nbpi, enter:
```
crfs -v jfs -g rootvg -m /test -a size=16M -a frag=512 -a nbpi=1024
```
This command creates the /test file system on the rootvg volume group with a fragment size of 512 bytes, a number of bytes per i-node (nbpi) ratio of 1024, and an initial size of 16MB.

Files

/etc/filesystems

Lists the known file systems and defines their characteristics.

Related Information

The chfs command, mkfs command, mklv command.

The File Systems in AIX 5L Version 5.2 System Management Concepts: Operating System and Devices explains file system types, management, structure, and maintenance.

For information on installing the Web-based System Manager, see Chapter 2: Installation and System Requirements in AIX 5L Version 5.2 Web-based System Manager Administration Guide.

The System Management Interface Tool in AIX 5L Version 5.2 System Management Concepts: Operating System and Devices explains SMIT structure, main menus, and tasks.

Understanding Journaled File System Size Limitations in AIX 5L Version 5.2 System Management Concepts: Operating System and Devices.