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newfs(8) System Manager's Manual newfs(8) NAME newfs, mfs - Constructs a new UFS file system SYNOPSIS /usr/sbin/newfs [-N] [newfs-options] special-device [disk-type] /usr/sbin/mfs [-F mount-flags] [newfs-options] [special-device] mount- node DESCRIPTION The newfs command creates a new UFS file system on the specified spe- cial-device of type disk-type. The newfs command cannot be used to create Advanced File System (AdvFS) domains. Instead, use the mkfdmn command, as described in the mkfdmn(8) reference page. If the disk has been labeled using the disklabel command, newfs builds a UFS file system on the specified device, basing its defaults on the information in the disk label. If the disk has not been labeled using the disklabel command, newfs fails. In this case, use the disklabel command to install a label. The mfs command builds a memory file system (mfs), which is a UFS file system in virtual memory, and mounts it on the specified mount-node. When the file system is unmounted, mfs exits and the contents of the file system are lost. If mfs is sent a signal while running, for exam- ple during system shutdown, it attempts to unmount its corresponding file system. The parameters for mfs are almost the same as those for newfs. For a memory file system, the special-device file provides only a set of configuration parameters, including the size of the virtual memory segment to allocate. If the special-device file is omitted, you must specify the segment size. The special-device file is usually the primary swap area, because that is where the file system is backed up when free memory gets low and the memory supporting the file system has to be paged. You can enable /tmp as a memory file system by adding an entry in the /etc/fstab file. For example, the following line creates a 10 Megabyte memory file system, mounted on /tmp: -s20480 /tmp mfs rw 1 0 Note that the contents of a memory file system are lost whenever a re- boot or unmount is performed. You must be superuser to use either command. FLAGS This section describes the file system dependencies for the UFS file systems. Displays the file system parameters without creating the file system. The following newfs-options flags define the general layout policies. The block size of the file system in bytes. Note that the block size is fixed at 8KB. The fragment size of the file system in bytes. The percentage of space reserved from normal users; the minimum free space threshold (minfree). The default value is 10%. See tunefs(8) for more details on how to set this option. The file system can either be in- structed to try to minimize the time spent allocating blocks, or to try to minimize the space fragmentation on the disk. If the value of min- free is less than 10%, the default is to optimize for space; if the value of minfree is greater than or equal to 10%, the default is to op- timize for time. See tunefs(8) for more details on how to set this op- tion. This specifies the maximum number of contiguous blocks that are laid out before forcing a rotational delay (refer to the -d option); that is, the number of blocks that can be combined into a single read request (cluster). The default value is 8. See tunefs(8) for more de- tails on how to set this option. This specifies the expected time (in milliseconds) to service a transfer completion interrupt and initiate a new transfer on the same disk. The default is zero milliseconds. See tunefs(8) for more details on how to set this option. This indicates the maximum number of blocks any single file can allocate out of a cylinder group before it is forced to begin allocating blocks from an- other cylinder group. The default is about one-quarter of the total blocks in a cylinder group. See tunefs(8) for more details on how to set this option. This specifies the density of inodes in the file sys- tem. The default is to create an inode for each 4096 bytes of data space. If fewer inodes are desired, a larger number should be used; to create more inodes a smaller number should be given. The number of cylinders per cylinder group in a file system. The default value is 16. The size of the file system in sectors. The following options override the default sizes for the disk geometry. The default values are taken from the disk label. Changing the de- faults is useful only if you are using newfs to build (create) a file system whose raw image will eventually be used on a different type of disk (on a write-once disk, for example). Note that changing any of these values from their defaults makes it impossible for fsck to find the alternate superblocks if the standard superblock is lost. The speed of the disk in revolutions per minute. The size of a sector in bytes (almost never anything but 512). The number of sectors per track available for data allocation by the file system. This does not in- clude sectors reserved at the end of each track for bad block replace- ment (see -p). The number of tracks per cylinder available for data allocation by the file system. Spare sectors (bad sector replacements) are physical sectors that occupy space at the end of each track. They are not counted as part of the sectors per track (-u) since they are not available to the file system for data allocation. Spare sectors (bad sector replacements) are physical sectors that occupy space at the end of the last track in the cylinder. They are deducted from the sec- tors per track (-u) of the last track of each cylinder since they are not available to the file system for data allocation. Used to describe perturbations in the media format to compensate for a slow controller. Interleave is physical sector interleave on each track, specified as the denominator of the ratio: sectors read/sectors passed over. Thus, an interleave of 1/1 implies contiguous layout, while 1/2 implies logical sector 0 (zero) is separated by one sector from logical sector 1. Used to describe perturbations in the media format to compensate for a slow controller. Track skew is the offset of sector 0 (zero) on track N relative to sector 0 (zero) on track N-1 on the same cylinder. The following option applies only to mfs: Used for providing a decimal numeric value to be passed as mount flags when running as a memory based file sys- tem. This option is primarily intended for use when mfs is started by the mount(8) command. NOTES When using newfs to create a UFS file system on an LSM volume, follow these guidelines: The disk-type variable may be specified to enable newfs to obtain disk attributes such as number of sectors (ns), number of tracks (nt), and number of cylinders (nc) from the /etc/disktab file. The newfs command may get this information from /etc/disktab be- cause an LSM volume has no disk label. When specifying disk-type, you can use any entry in /etc/disktab that has positive values for the disk attributes (except rx## entries). Since the entries for disks with dy- namic geometry (such as RAID, re, SWXCR, and hsz##) have a value of -1 for these attributes, such disk types cannot be specified to newfs. Instead, use another entry whose characteristics match those of the volume (for example, rz##). Or, you can create a customized entry in /etc/disktab. The -s option can be omitted, because newfs queries LSM for the size of the LSM volume. If the -s option is specified, it overrides the LSM query. ERRORS You may receive the following messages when using the newfs command: newfs: /dev/rvol/diskgroup/volname: only 0 partitions This error occurs when you attempt to create a file system on an LSM volume and fail to specify the disk-type parameter cor- rectly. See the NOTES section for details. Warning: nn sec- tor(s) in last cylinder unallocated This message is for UFS only. It requires no user action. The message indicates that if nn sectors are added to the size of the file system, it will be an integral number of cylinders. Disk space is not wasted. Usually, cylinder boundaries are ig- nored when partitions are allocated. Warning: inode blocks/cyl group (inumber) >= data blocks (dnumber) in last cylinder group. This implies snumber sector(s) cannot be allocated This message requires no user action. It indicates that inumber of file system blocks were needed to allocate the inode table but only dnumber of file system blocks were available in the last cylinder group. The last cylinder group could not be allo- cated and snumber of sectors are actually wasted. Warning: spe- cial-device and overlapping partition(s) are marked in use. If you continue with the operation you can possibly destroy ex- isting data. CONTINUE? [y/n] The specified partition overlaps with another partition or par- titions that has the fstype field set. Warning: partition(s) which overlap special-device are marked in use. If you continue with the operation you can possibly destroy ex- isting data. CONTINUE? [y/n] The specified partition overlaps with another partition or par- titions that has the fstype field set. Warning: special-device is marked in use for fstype in the disklabel. The partition you are changing already has a file system on it. This is not an error just a warning. The partition you are changing already has a file system on it. special-device is marked in use for fstype in the disklabel. If you continue with the operation you can possibly destroy ex- isting data. CONTINUE? [y/n] This message indicates that you tried to create a file system on a partition that is not currently in active use but is marked for use in the disk label's partition map. For example, the par- tition may be part of an LSM volume or an AdvFS domain. If you know that the partition you specified to newfs does not contain any useful data, you can choose to override the warning. In this case, the fstype in the disk label will be modified to 4.2BSD. Note that you can use the command disklabel -s to set the fstype in the disk label to unused for partitions that do not contain any valid data. See disklabel(8) for more information. Parti- tion(s) which overlap special-device are marked in use. If you continue with the operation you can possibly destroy ex- isting data. CONTINUE? [y/n] This message indicates that the partition you specified is not marked for use, but other, overlapping partitions on the disk are marked for use. If you override this warning, the fstype in the disk's label will be modified. The partition you specified to newfs will be marked as in use by the UFS file system and la- beled with 4.2BSD. All overlapping partitions will be marked UNUSED. special-device or an overlapping partition is open. Quitting... This message indicates that you tried to create a file system on a partition that is actively in use. Error: the disklabel for special-device does not exist or is corrupted. Quitting .... The specified device either does not have a disklabel or the disklabel is corrupted. Error: special-device or an overlapping partition is open. Quitting .... This message indicates that you tried to create a file system on a partition that is open. Error: special-device is an invalid device or cannot be opened. Quitting .... The specified device is either an invalid device or it cannot be opened. Error: the disklabel for special-device could not be updated. Quitting .... This message indicates that the disklabel on the specified de- vice could not be updated. Error:: unable to check special-de- vice against active AdvFS domains because the directory /etc/fdmns seems to be missing or wrong. Quitting .... This message indicates that there was a failure when checking overlap with AdvFS domains. Either /etc/fdmns or /etc/fdmns/dom are not active domains or they do not exist. Error: unable to check special-device against active swap devices because special swap files are missing. Quitting .... This message indicates that there was a failure when checking overlap with active swap devices. The special device files as- sociated with active swap devices are invalid. Error: unknown overlap condition errno encountered for partition special-de- vice. Quitting .... This message indicates that an unknown error was detected. The following examples illustrate some of these messages: Creating a file system on a partition that is marked for use: # /usr/sbin/newfs /dev/rrz11g /dev/rrz11g is marked in use for LSMpubl in the disklabel. If you con- tinue with the operation you can possibly destroy existing data. CON- TINUE? [y/n] Partition g of disk rz11 is part of a disk marked for use by LSM. If LSM is not actively using this partition and the parti- tion does not contain any useful data, you may want to override this warning, by answering y. In this case, partition g will be marked as 4.2BSD in the disk label. Creating a file system on a partition whose overlapping partitions are marked for use: # /usr/sbin/newfs /dev/rrz11c Partition(s) which overlap /dev/rrz11c are marked in use. If you continue with the operation you can possibly destroy exist- ing data. CONTINUE? [y/n] If you answer y, partition c on disk rz11 will be marked 4.2BSD in the disk label and all partitions that overlap c will be marked UNUSED. Creating a file system on a partition that is open: # /usr/sbin/newfs /dev/rrz11g /dev/rrz11g or an overlapping partition is open. Quitting... Creating a file system on disk that does not have a disk label: # /usr/sbin/newfs /dev/rrz11c The disklabel for /dev/rrz11c does not exist or is corrupted. Quitting... See for information on installing a disk label on a disk. FILES Specifies the command path. Specifies the command path. Provides disk geometry and file system partition information. RELATED INFORMATION Commands: chmod(1), disklabel(8), fsck(8), mkfdmn(8), mount(8), tunefs(8) Files: disktab(4), fstab(4) Functions: check_usage(3), set_usage(3) delim off newfs(8)