|System Administration Commands||newfs(1M)
| ||newfs - construct a new UFS file system
| ||newfs [-Nv] [mkfs-options] raw-device
newfs is a "friendly" front-end to the mkfs(1M) program for making UFS file systems on disk partitions. newfs calculates
the appropriate parameters to use and calls mkfs.
If run interactively (that is, standard input is a tty), newfs will prompt for confirmation before making the file system.
If the -N option is not specified and the inodes of the device are not randomized, newfs will call fsirand(1M).
You must be super-user to use this command, except when creating a UFS file system on a diskette (see EXAMPLES).
The following options are supported:
- Print out the file system parameters that would be used in creating the file system without actually creating the file system. fsirand(1M) is not called here.
- Verbose. newfs prints out its actions, including the parameters passed to mkfs.
- Options that override the default parameters are:
- -a apc
- The number of alternate sectors per cylinder (SCSI devices only) to reserve for bad block replacement. The default is 0.
- -b bsize
- The logical block size of the file system in bytes (either 4096 or 8192). The default is 8192. The sun4u architecture does not support the 4096 block size.
- -c cgsize
- The number of cylinders per cylinder group (ranging from 16 to 256). The default is calculated by dividing the number of sectors in the file system by the number of sectors
in a gigabyte, and then multiplying the result by 32. The default value will always be between 16 and 256. mkfs may override this value. See mkfs_ufs(1M) for details.
- -C maxcontig
- The maximum number of logical blocks, belonging to one file, that will be allocated contiguously before inserting a rotational delay. The default is determined from the disk drive's maximum transfer rate.
UFS supports no more than 1048576 byte (1MB) runs. With a logical block size of 4096, this gives a maxcontig limit of 256. With 8192, the limit is 128.
This parameter can be subsequently changed using the tunefs(1M) command.
This parameter also controls clustering. Regardless of the value of gap, clustering is enabled only when maxcontig is greater than 1. Clustering allows higher I/O rates for sequential I/O and is described in tunefs(1M).
- -d gap
- Rotational delay. The expected time (in milliseconds) to service a transfer completion interrupt and initiate a new transfer on the same disk. It is used to decide how much rotational spacing to place between successive
blocks in a file. This parameter can be subsequently changed using the tunefs(1M) command. The default is 0.
- -f fragsize
- The smallest amount of disk space in bytes to allocate to a file. The smallest amout of disk space in bytes to allocate to a file. If the logical block size is 4096, legal values are 512, 1024, 2048, and 4096. When the logical block size is 8192, legal values are 1024, 2048, 4096, and 8192. The default value is 1024.
- -i nbpi
- The number of bytes per inode. This specifies the density of inodes in the file system. The number is divided into the total size of the file system to determine the fixed number of inodes to create. It should
reflect the expected average size of files in the file system. If fewer inodes are desired, a larger number should be used; to create more inodes a smaller number should be given. The default for nbpi is as follows:.
Disk size Density
- -m free
- The minimum percentage of free space to maintain in the file system (between 1% and 99%, inclusively). This space is off-limits to normal users. Once the file system is filled to this threshold, only the super-user
can continue writing to the file system. This parameter can be subsequently changed using the tunefs(1M) command.
The default is ((64 Mbytes/partition size) * 100), rounded down to the nearest integer and limited between 1% and 10%, inclusively.
- -n nrpos
- The number of different rotational positions in which to divide a cylinder group. The default is 8.
- -o opt
- (space or time). The file system can either be instructed to try to minimize the time spent allocating blocks, or to try to minimize the space fragmentation on the disk. The
default is time.
- -r rpm
- The speed of the disk in revolutions per minute. The default is driver- or device-specific.
- -s size
- The size of the file system in sectors. The default is to use the entire partition.
- -t ntrack
- The number of tracks per cylinder on the disk. The default is taken from the disk label.
The following operands are supported:
- The name of a raw special device residing in /dev/rdsk (for example, /dev/rdsk/c0t0d0s6) on which to create the file system.
See largefile(5) for the description of the behavior of newfs when encountering files greater than or equal to 2 Gbyte ( 231 bytes).
| ||Example 1. Verbosely displaying the parameters for the raw special device.
Example 2. Creating a UFS file system.
The following example verbosely displays the parameters for the raw special device, c0t0d0s6, but does not actually create a new file system:
example# newfs -Nv /dev/rdsk/c0t0d0s6
mkfs -F ufs -o N /dev/rdsk/c0t0d0s6 1112940 54 15 8192 1024 16 10 60
2048 t 0 -1 8 /dev/rdsk/c0t0d0s6: 1112940 sectors in
1374 cylinders of 15 tracks, 54 sectors 569.8MB in 86 cyl
groups (16 c/g, 6.64MB/g, 3072 i/g) super-block backups
(for fsck -b #) at:
32, 13056, 26080, 39104, 52128, 65152, 78176, 91200, 104224, ...
The following example uses the command to create a UFS file system on a diskette that is managed by Volume Manager.
example% newfs /vol/dev/aliases/floppy0
newfs: construct a new file system /vol/dev/aliases/floppy0: (y/n)? y
/vol/dev/aliases/floppy0: 2880 sectors in 80 cylinders of 2 tracks,
18 sectors 1.4MB in 5 cyl groups (16 c/g, 0.28MB/g, 128 i/g)
super-block backups (for fsck -F ufs -o b=#) at:
32, 640, 1184, 1792, 2336, ...
The following exit values are returned:
- The operation was successful.
- Usage error or internal error. A message is output to STDERR explaining the error.
Other exit values may be returned by mkfs(1M), which is called by newfs.
See attributes(5) for descriptions of the following attributes:
|ATTRIBUTE TYPE||ATTRIBUTE VALUE
newfs: No such file or directory
- The device specified does not exist, or a disk partition was not specified.
special: cannot open
- You must be super-user to use this command.