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NetBSD 6.1.5 - man page for newfs_lfs (netbsd section 8)

NEWFS_LFS(8)			   BSD System Manager's Manual			     NEWFS_LFS(8)

NAME
     newfs_lfs -- construct a new LFS file system

SYNOPSIS
     newfs_lfs [newfs_lfs-options] special

DESCRIPTION
     newfs_lfs builds a log-structured file system on the specified special device basing its
     defaults on the information in the disk label.  Before running newfs_lfs the disk must be
     labeled using disklabel(8), the proper fstype is 4.4LFS.  Reasonable values for the fsize,
     bsize, and sgs fields are 1024, 8192, and 7 respectively.

     The following options define the general layout policies.

     -A 	 Attempt to compute the appropriate segment size using the formula 4 * bandwidth
		 * access time.  The disk is tested for twenty seconds to discover its bandwidth
		 and seek time.

     -B logical-segment-size
		 The logical segment size of the file system in bytes.	If not specified, the
		 segment size is computed by left-shifting the partition label's block size by
		 the amount indicated in the partition table's segshift.  If the disklabel indi-
		 cates a zero block size or segment shift, a compile-time default segment size of
		 1M is used.

     -b block-size
		 The block size of the file system in bytes.  If not specified, the block size is
		 taken from the partition label, or if the partition label indicates 0, a com-
		 pile-time default of 8K is used.

     -F 	 Force creation of an LFS even on a partition labeled as another type.	newfs_lfs
		 will use compile-time default values for block and fragment size, and segment
		 shift, unless these are overridden by command-line flags.

     -f fragment-size
		 The fragment size of the file system in bytes.  If not specified, the fragment
		 size is taken from the partition label, or if the partition label indicates 0, a
		 compile-time default of 1K is used.

     -I interleave
		 Specify the interleave between segments.  The default is zero.

     -i 	 The size of an inode block, in bytes.	The default is to use the same size as a
		 fragment, or in a v1 filesystem, the same size as a data block.

     -L 	 Create a log-structured file system (LFS).  This is the default, and this option
		 is provided for compatibility only.

     -M nsegs	 Specify lfs_minfreeseg, the number of segments left out of the amount allocated
		 to user data.	A higher number increases cleaner performance, while a lower num-
		 ber gives more usable space.  The default is based on the size of the filesys-
		 tem, either 5% of the total number of segments or 20 segments, whichever is
		 larger.

     -m free space %
		 The percentage of space reserved from normal users; the minimum free space
		 threshold.  The default value used is 10%.

     -N 	 Do not actually create the filesystem.

     -O offset	 Start the first segment this many sectors from the beginning of the partition.
		 The default is zero.

     -R nsegs	 Specify lfs_resvseg, the number of segments set aside for the exclusive use of
		 the cleaner.  A larger figure reduces the likelihood of running out of clean
		 segments, but if lfs_resvseg is too close to lfs_minfreeseg, the cleaner will
		 run without ceasing when the filesystem becomes close to full.  The default is
		 the larger of 15 or the quantity lfs_minfreeseg / 2 + 1 .

     -r ident	 For a v2 filesystem, specify the roll-forward identifier for the filesystem.
		 This identifier, a 32-bit numeric quantity, should be different from that of any
		 LFS that may previously have existed on the same disk.  By default the identi-
		 fier is chosen at random.

     -s size	 The size of the file system in sectors.

     -v version  Make a filesystem with the specified disk layout version.  Valid options are 1
		 or 2 (the default).  Note, however, that LFS version 1 is deprecated.

SEE ALSO
     disktab(5), disklabel(8), diskpart(8), dumplfs(8)

     M. Seltzer, K. Bostic, M. McKusick, and C. Staelin, "An Implementation of a Log-Structured
     File System for UNIX", Proceedings of the Winter 1993 USENIX Conference, pp. 315-331,
     January 25-29, 1993.

     J. Matthews, D. Roselli, A. Costello, R. Wang, and T. Anderson, "Improving the Performance
     of Log-Structured File Systems with Adaptive Methods", Proceedings of the Sixteenth ACM
     SOSP, October 1997.

HISTORY
     A newlfs command appeared in 4.4BSD, and was renamed to newfs_lfs for NetBSD 1.4.

BSD					  July 12, 2001 				      BSD


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