MKFS(8)                                                                MKFS(8)



NAME
       mkfs - construct a file system

SYNOPSIS
       /etc/mkfs  [  -N ] special size [ nsect [ ntrack [ blksize [ fragsize [
       ncpg [ minfree [ rps [ nbpi [ opt ] ] ] ] ] ] ] ] ]

DESCRIPTION
       N.B.: file system are normally created with the _n_e_w_f_s(8) command.

       _M_k_f_s constructs a file system by writing on the  special  file  _s_p_e_c_i_a_l
       unless  the -N flag has been specified.  The numeric size specifies the
       number of sectors in the file system.  _M_k_f_s builds a file system with a
       root directory and a _l_o_s_t_+_f_o_u_n_d directory.  (see _f_s_c_k(8)) The number of
       i-nodes is calculated as a function of the file system size.   No  boot
       program is initialized by _m_k_f_s (see _n_e_w_f_s(8).)

       The  optional  arguments allow fine tune control over the parameters of
       the file system.  Nsect specify the number of sectors per track on  the
       disk.   Ntrack  specify  the number of tracks per cylinder on the disk.
       Blksize gives the primary block size for files on the file system.   It
       must be a power of two, currently selected from 4096 or 8192.  Fragsize
       gives the fragment size for files on the  file  system.   The  fragsize
       represents  the smallest amount of disk space that will be allocated to
       a file.  It must be a power of two currently selected  from  the  range
       512  to 8192.  Ncpg specifies the number of disk cylinders per cylinder
       group.  This number must be in the range 1 to  32.   Minfree  specifies
       the  minimum percentage of free disk space allowed.  Once the file sys‐
       tem capacity reaches this threshold, only the super-user is allowed  to
       allocate  disk  blocks.   The default value is 10%.  If a disk does not
       revolve at 60 revolutions per second, the rps parameter may  be  speci‐
       fied.   If a file system will have more or less than the average number
       of files the nbpi (number of bytes  per  inode)  can  be  specified  to
       increase  or  decrease the number of inodes that are created.  Space or
       time optimization preference can be specified with opt values of  ‘‘s’’
       for space or ‘‘t’’ for time.  Users with special demands for their file
       systems are referred to the paper cited below for a discussion  of  the
       tradeoffs in using different configurations.

SEE ALSO
       fs(5), dir(5), fsck(8), newfs(8), tunefs(8)

       M.  McKusick,  W.  Joy,  S. Leffler, R. Fabry, ‘‘A Fast File System for
       UNIX’’, _A_C_M _T_r_a_n_s_a_c_t_i_o_n_s _o_n _C_o_m_p_u_t_e_r _S_y_s_t_e_m_s _2, 3.  pp 181-197,  August
       1984.  (reprinted in the System Manager’s Manual, SMM:14)

BUGS
       There should be some way to specify bad blocks.



4th Berkeley Distribution        May 21, 1986                          MKFS(8)