Incorporate the enhanced ffs_dirpref() by Grigoriy Orlov, as found in
FreeBSD (three commits; the initial work, man page updates, and a fix
to ffs_reload()), with the following differences:
- Be consistent between newfs(8) and tunefs(8) as to the options which
set and control the tuning parameters for this work (avgfilesize & avgfpdir)
- Use u_int16_t instead of u_int8_t to keep track of the number of
contiguous directories (suggested by Chuck Silvers)
- Work within our FFS_EI framework
- Ensure that fs->fs_maxclusters and fs->fs_contigdirs don't point to
the same area of memory
The new algorithm has a marked performance increase, especially when
performing tasks such as untarring pkgsrc.tar.gz, etc.
The original FreeBSD commit messages are attached:
=====
mckusick 2001/04/10 01:39:00 PDT
Directory layout preference improvements from Grigoriy Orlov <gluk@ptci.ru>.
His description of the problem and solution follow. My own tests show
speedups on typical filesystem intensive workloads of 5% to 12% which
is very impressive considering the small amount of code change involved.
------
One day I noticed that some file operations run much faster on
small file systems then on big ones. I've looked at the ffs
algorithms, thought about them, and redesigned the dirpref algorithm.
First I want to describe the results of my tests. These results are old
and I have improved the algorithm after these tests were done. Nevertheless
they show how big the perfomance speedup may be. I have done two file/directory
intensive tests on a two OpenBSD systems with old and new dirpref algorithm.
The first test is "tar -xzf ports.tar.gz", the second is "rm -rf ports".
The ports.tar.gz file is the ports collection from the OpenBSD 2.8 release.
It contains 6596 directories and 13868 files. The test systems are:
1. Celeron-450, 128Mb, two IDE drives, the system at wd0, file system for
test is at wd1. Size of test file system is 8 Gb, number of cg=991,
size of cg is 8m, block size = 8k, fragment size = 1k OpenBSD-current
from Dec 2000 with BUFCACHEPERCENT=35
2. PIII-600, 128Mb, two IBM DTLA-307045 IDE drives at i815e, the system
at wd0, file system for test is at wd1. Size of test file system is 40 Gb,
number of cg=5324, size of cg is 8m, block size = 8k, fragment size = 1k
OpenBSD-current from Dec 2000 with BUFCACHEPERCENT=50
You can get more info about the test systems and methods at:
http://www.ptci.ru/gluk/dirpref/old/dirpref.html
Test Results
tar -xzf ports.tar.gz rm -rf ports
mode old dirpref new dirpref speedup old dirprefnew dirpref speedup
First system
normal 667 472 1.41 477 331 1.44
async 285 144 1.98 130 14 9.29
sync 768 616 1.25 477 334 1.43
softdep 413 252 1.64 241 38 6.34
Second system
normal 329 81 4.06 263.5 93.5 2.81
async 302 25.7 11.75 112 2.26 49.56
sync 281 57.0 4.93 263 90.5 2.9
softdep 341 40.6 8.4 284 4.76 59.66
"old dirpref" and "new dirpref" columns give a test time in seconds.
speedup - speed increasement in times, ie. old dirpref / new dirpref.
------
Algorithm description
The old dirpref algorithm is described in comments:
/*
* Find a cylinder to place a directory.
*
* The policy implemented by this algorithm is to select from
* among those cylinder groups with above the average number of
* free inodes, the one with the smallest number of directories.
*/
A new directory is allocated in a different cylinder groups than its
parent directory resulting in a directory tree that is spreaded across
all the cylinder groups. This spreading out results in a non-optimal
access to the directories and files. When we have a small filesystem
it is not a problem but when the filesystem is big then perfomance
degradation becomes very apparent.
What I mean by a big file system ?
1. A big filesystem is a filesystem which occupy 20-30 or more percent
of total drive space, i.e. first and last cylinder are physically
located relatively far from each other.
2. It has a relatively large number of cylinder groups, for example
more cylinder groups than 50% of the buffers in the buffer cache.
The first results in long access times, while the second results in
many buffers being used by metadata operations. Such operations use
cylinder group blocks and on-disk inode blocks. The cylinder group
block (fs->fs_cblkno) contains struct cg, inode and block bit maps.
It is 2k in size for the default filesystem parameters. If new and
parent directories are located in different cylinder groups then the
system performs more input/output operations and uses more buffers.
On filesystems with many cylinder groups, lots of cache buffers are
used for metadata operations.
My solution for this problem is very simple. I allocate many directories
in one cylinder group. I also do some things, so that the new allocation
method does not cause excessive fragmentation and all directory inodes
will not be located at a location far from its file's inodes and data.
The algorithm is:
/*
* Find a cylinder group to place a directory.
*
* The policy implemented by this algorithm is to allocate a
* directory inode in the same cylinder group as its parent
* directory, but also to reserve space for its files inodes
* and data. Restrict the number of directories which may be
* allocated one after another in the same cylinder group
* without intervening allocation of files.
*
* If we allocate a first level directory then force allocation
* in another cylinder group.
*/
My early versions of dirpref give me a good results for a wide range of
file operations and different filesystem capacities except one case:
those applications that create their entire directory structure first
and only later fill this structure with files.
My solution for such and similar cases is to limit a number of
directories which may be created one after another in the same cylinder
group without intervening file creations. For this purpose, I allocate
an array of counters at mount time. This array is linked to the superblock
fs->fs_contigdirs[cg]. Each time a directory is created the counter
increases and each time a file is created the counter decreases. A 60Gb
filesystem with 8mb/cg requires 10kb of memory for the counters array.
The maxcontigdirs is a maximum number of directories which may be created
without an intervening file creation. I found in my tests that the best
performance occurs when I restrict the number of directories in one cylinder
group such that all its files may be located in the same cylinder group.
There may be some deterioration in performance if all the file inodes
are in the same cylinder group as its containing directory, but their
data partially resides in a different cylinder group. The maxcontigdirs
value is calculated to try to prevent this condition. Since there is
no way to know how many files and directories will be allocated later
I added two optimization parameters in superblock/tunefs. They are:
int32_t fs_avgfilesize; /* expected average file size */
int32_t fs_avgfpdir; /* expected # of files per directory */
These parameters have reasonable defaults but may be tweeked for special
uses of a filesystem. They are only necessary in rare cases like better
tuning a filesystem being used to store a squid cache.
I have been using this algorithm for about 3 months. I have done
a lot of testing on filesystems with different capacities, average
filesize, average number of files per directory, and so on. I think
this algorithm has no negative impact on filesystem perfomance. It
works better than the default one in all cases. The new dirpref
will greatly improve untarring/removing/coping of big directories,
decrease load on cvs servers and much more. The new dirpref doesn't
speedup a compilation process, but also doesn't slow it down.
Obtained from: Grigoriy Orlov <gluk@ptci.ru>
=====
=====
iedowse 2001/04/23 17:37:17 PDT
Pre-dirpref versions of fsck may zero out the new superblock fields
fs_contigdirs, fs_avgfilesize and fs_avgfpdir. This could cause
panics if these fields were zeroed while a filesystem was mounted
read-only, and then remounted read-write.
Add code to ffs_reload() which copies the fs_contigdirs pointer
from the previous superblock, and reinitialises fs_avgf* if necessary.
Reviewed by: mckusick
=====
=====
nik 2001/04/10 03:36:44 PDT
Add information about the new options to newfs and tunefs which set the
expected average file size and number of files per directory. Could do
with some fleshing out.
=====
2001-09-06 06:16:00 +04:00
|
|
|
.\" $NetBSD: newfs.8,v 1.33 2001/09/06 02:16:01 lukem Exp $
|
1995-03-18 17:54:19 +03:00
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|
.\"
|
1994-06-08 23:27:32 +04:00
|
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|
.\" Copyright (c) 1983, 1987, 1991, 1993, 1994
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.\" The Regents of the University of California. All rights reserved.
|
1993-03-21 12:45:37 +03:00
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
|
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.\" notice, this list of conditions and the following disclaimer.
|
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|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
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|
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|
.\" notice, this list of conditions and the following disclaimer in the
|
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|
.\" documentation and/or other materials provided with the distribution.
|
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|
.\" 3. All advertising materials mentioning features or use of this software
|
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|
.\" must display the following acknowledgement:
|
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|
.\" This product includes software developed by the University of
|
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|
.\" California, Berkeley and its contributors.
|
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|
.\" 4. Neither the name of the University nor the names of its contributors
|
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|
.\" may be used to endorse or promote products derived from this software
|
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|
.\" without specific prior written permission.
|
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
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.\" SUCH DAMAGE.
|
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.\"
|
1997-09-16 18:05:39 +04:00
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|
.\" @(#)newfs.8 8.6 (Berkeley) 5/3/95
|
1993-03-22 11:04:00 +03:00
|
|
|
.\"
|
Incorporate the enhanced ffs_dirpref() by Grigoriy Orlov, as found in
FreeBSD (three commits; the initial work, man page updates, and a fix
to ffs_reload()), with the following differences:
- Be consistent between newfs(8) and tunefs(8) as to the options which
set and control the tuning parameters for this work (avgfilesize & avgfpdir)
- Use u_int16_t instead of u_int8_t to keep track of the number of
contiguous directories (suggested by Chuck Silvers)
- Work within our FFS_EI framework
- Ensure that fs->fs_maxclusters and fs->fs_contigdirs don't point to
the same area of memory
The new algorithm has a marked performance increase, especially when
performing tasks such as untarring pkgsrc.tar.gz, etc.
The original FreeBSD commit messages are attached:
=====
mckusick 2001/04/10 01:39:00 PDT
Directory layout preference improvements from Grigoriy Orlov <gluk@ptci.ru>.
His description of the problem and solution follow. My own tests show
speedups on typical filesystem intensive workloads of 5% to 12% which
is very impressive considering the small amount of code change involved.
------
One day I noticed that some file operations run much faster on
small file systems then on big ones. I've looked at the ffs
algorithms, thought about them, and redesigned the dirpref algorithm.
First I want to describe the results of my tests. These results are old
and I have improved the algorithm after these tests were done. Nevertheless
they show how big the perfomance speedup may be. I have done two file/directory
intensive tests on a two OpenBSD systems with old and new dirpref algorithm.
The first test is "tar -xzf ports.tar.gz", the second is "rm -rf ports".
The ports.tar.gz file is the ports collection from the OpenBSD 2.8 release.
It contains 6596 directories and 13868 files. The test systems are:
1. Celeron-450, 128Mb, two IDE drives, the system at wd0, file system for
test is at wd1. Size of test file system is 8 Gb, number of cg=991,
size of cg is 8m, block size = 8k, fragment size = 1k OpenBSD-current
from Dec 2000 with BUFCACHEPERCENT=35
2. PIII-600, 128Mb, two IBM DTLA-307045 IDE drives at i815e, the system
at wd0, file system for test is at wd1. Size of test file system is 40 Gb,
number of cg=5324, size of cg is 8m, block size = 8k, fragment size = 1k
OpenBSD-current from Dec 2000 with BUFCACHEPERCENT=50
You can get more info about the test systems and methods at:
http://www.ptci.ru/gluk/dirpref/old/dirpref.html
Test Results
tar -xzf ports.tar.gz rm -rf ports
mode old dirpref new dirpref speedup old dirprefnew dirpref speedup
First system
normal 667 472 1.41 477 331 1.44
async 285 144 1.98 130 14 9.29
sync 768 616 1.25 477 334 1.43
softdep 413 252 1.64 241 38 6.34
Second system
normal 329 81 4.06 263.5 93.5 2.81
async 302 25.7 11.75 112 2.26 49.56
sync 281 57.0 4.93 263 90.5 2.9
softdep 341 40.6 8.4 284 4.76 59.66
"old dirpref" and "new dirpref" columns give a test time in seconds.
speedup - speed increasement in times, ie. old dirpref / new dirpref.
------
Algorithm description
The old dirpref algorithm is described in comments:
/*
* Find a cylinder to place a directory.
*
* The policy implemented by this algorithm is to select from
* among those cylinder groups with above the average number of
* free inodes, the one with the smallest number of directories.
*/
A new directory is allocated in a different cylinder groups than its
parent directory resulting in a directory tree that is spreaded across
all the cylinder groups. This spreading out results in a non-optimal
access to the directories and files. When we have a small filesystem
it is not a problem but when the filesystem is big then perfomance
degradation becomes very apparent.
What I mean by a big file system ?
1. A big filesystem is a filesystem which occupy 20-30 or more percent
of total drive space, i.e. first and last cylinder are physically
located relatively far from each other.
2. It has a relatively large number of cylinder groups, for example
more cylinder groups than 50% of the buffers in the buffer cache.
The first results in long access times, while the second results in
many buffers being used by metadata operations. Such operations use
cylinder group blocks and on-disk inode blocks. The cylinder group
block (fs->fs_cblkno) contains struct cg, inode and block bit maps.
It is 2k in size for the default filesystem parameters. If new and
parent directories are located in different cylinder groups then the
system performs more input/output operations and uses more buffers.
On filesystems with many cylinder groups, lots of cache buffers are
used for metadata operations.
My solution for this problem is very simple. I allocate many directories
in one cylinder group. I also do some things, so that the new allocation
method does not cause excessive fragmentation and all directory inodes
will not be located at a location far from its file's inodes and data.
The algorithm is:
/*
* Find a cylinder group to place a directory.
*
* The policy implemented by this algorithm is to allocate a
* directory inode in the same cylinder group as its parent
* directory, but also to reserve space for its files inodes
* and data. Restrict the number of directories which may be
* allocated one after another in the same cylinder group
* without intervening allocation of files.
*
* If we allocate a first level directory then force allocation
* in another cylinder group.
*/
My early versions of dirpref give me a good results for a wide range of
file operations and different filesystem capacities except one case:
those applications that create their entire directory structure first
and only later fill this structure with files.
My solution for such and similar cases is to limit a number of
directories which may be created one after another in the same cylinder
group without intervening file creations. For this purpose, I allocate
an array of counters at mount time. This array is linked to the superblock
fs->fs_contigdirs[cg]. Each time a directory is created the counter
increases and each time a file is created the counter decreases. A 60Gb
filesystem with 8mb/cg requires 10kb of memory for the counters array.
The maxcontigdirs is a maximum number of directories which may be created
without an intervening file creation. I found in my tests that the best
performance occurs when I restrict the number of directories in one cylinder
group such that all its files may be located in the same cylinder group.
There may be some deterioration in performance if all the file inodes
are in the same cylinder group as its containing directory, but their
data partially resides in a different cylinder group. The maxcontigdirs
value is calculated to try to prevent this condition. Since there is
no way to know how many files and directories will be allocated later
I added two optimization parameters in superblock/tunefs. They are:
int32_t fs_avgfilesize; /* expected average file size */
int32_t fs_avgfpdir; /* expected # of files per directory */
These parameters have reasonable defaults but may be tweeked for special
uses of a filesystem. They are only necessary in rare cases like better
tuning a filesystem being used to store a squid cache.
I have been using this algorithm for about 3 months. I have done
a lot of testing on filesystems with different capacities, average
filesize, average number of files per directory, and so on. I think
this algorithm has no negative impact on filesystem perfomance. It
works better than the default one in all cases. The new dirpref
will greatly improve untarring/removing/coping of big directories,
decrease load on cvs servers and much more. The new dirpref doesn't
speedup a compilation process, but also doesn't slow it down.
Obtained from: Grigoriy Orlov <gluk@ptci.ru>
=====
=====
iedowse 2001/04/23 17:37:17 PDT
Pre-dirpref versions of fsck may zero out the new superblock fields
fs_contigdirs, fs_avgfilesize and fs_avgfpdir. This could cause
panics if these fields were zeroed while a filesystem was mounted
read-only, and then remounted read-write.
Add code to ffs_reload() which copies the fs_contigdirs pointer
from the previous superblock, and reinitialises fs_avgf* if necessary.
Reviewed by: mckusick
=====
=====
nik 2001/04/10 03:36:44 PDT
Add information about the new options to newfs and tunefs which set the
expected average file size and number of files per directory. Could do
with some fleshing out.
=====
2001-09-06 06:16:00 +04:00
|
|
|
.Dd September 6, 2001
|
1993-03-21 12:45:37 +03:00
|
|
|
.Dt NEWFS 8
|
2001-06-05 15:22:41 +04:00
|
|
|
.Os
|
1993-03-21 12:45:37 +03:00
|
|
|
.Sh NAME
|
|
|
|
|
.Nm newfs ,
|
1994-07-16 09:18:11 +04:00
|
|
|
.Nm mount_mfs
|
1993-03-21 12:45:37 +03:00
|
|
|
.Nd construct a new file system
|
|
|
|
|
.Sh SYNOPSIS
|
1999-03-07 14:02:05 +03:00
|
|
|
.Nm ""
|
2001-07-29 13:55:22 +04:00
|
|
|
.Op Fl B Ar byte-order
|
|
|
|
|
.Op Fl FNOZ
|
1994-06-08 23:27:32 +04:00
|
|
|
.Op Fl S Ar sector-size
|
2001-07-29 13:55:22 +04:00
|
|
|
.Op Fl T Ar disk-type
|
1996-12-26 07:37:18 +03:00
|
|
|
.Op Fl a Ar maxcontig
|
1994-06-08 23:27:32 +04:00
|
|
|
.Op Fl b Ar block-size
|
2001-07-29 13:55:22 +04:00
|
|
|
.Op Fl c Ar cpg
|
1994-06-08 23:27:32 +04:00
|
|
|
.Op Fl d Ar rotdelay
|
|
|
|
|
.Op Fl e Ar maxbpg
|
|
|
|
|
.Op Fl f Ar frag-size
|
Incorporate the enhanced ffs_dirpref() by Grigoriy Orlov, as found in
FreeBSD (three commits; the initial work, man page updates, and a fix
to ffs_reload()), with the following differences:
- Be consistent between newfs(8) and tunefs(8) as to the options which
set and control the tuning parameters for this work (avgfilesize & avgfpdir)
- Use u_int16_t instead of u_int8_t to keep track of the number of
contiguous directories (suggested by Chuck Silvers)
- Work within our FFS_EI framework
- Ensure that fs->fs_maxclusters and fs->fs_contigdirs don't point to
the same area of memory
The new algorithm has a marked performance increase, especially when
performing tasks such as untarring pkgsrc.tar.gz, etc.
The original FreeBSD commit messages are attached:
=====
mckusick 2001/04/10 01:39:00 PDT
Directory layout preference improvements from Grigoriy Orlov <gluk@ptci.ru>.
His description of the problem and solution follow. My own tests show
speedups on typical filesystem intensive workloads of 5% to 12% which
is very impressive considering the small amount of code change involved.
------
One day I noticed that some file operations run much faster on
small file systems then on big ones. I've looked at the ffs
algorithms, thought about them, and redesigned the dirpref algorithm.
First I want to describe the results of my tests. These results are old
and I have improved the algorithm after these tests were done. Nevertheless
they show how big the perfomance speedup may be. I have done two file/directory
intensive tests on a two OpenBSD systems with old and new dirpref algorithm.
The first test is "tar -xzf ports.tar.gz", the second is "rm -rf ports".
The ports.tar.gz file is the ports collection from the OpenBSD 2.8 release.
It contains 6596 directories and 13868 files. The test systems are:
1. Celeron-450, 128Mb, two IDE drives, the system at wd0, file system for
test is at wd1. Size of test file system is 8 Gb, number of cg=991,
size of cg is 8m, block size = 8k, fragment size = 1k OpenBSD-current
from Dec 2000 with BUFCACHEPERCENT=35
2. PIII-600, 128Mb, two IBM DTLA-307045 IDE drives at i815e, the system
at wd0, file system for test is at wd1. Size of test file system is 40 Gb,
number of cg=5324, size of cg is 8m, block size = 8k, fragment size = 1k
OpenBSD-current from Dec 2000 with BUFCACHEPERCENT=50
You can get more info about the test systems and methods at:
http://www.ptci.ru/gluk/dirpref/old/dirpref.html
Test Results
tar -xzf ports.tar.gz rm -rf ports
mode old dirpref new dirpref speedup old dirprefnew dirpref speedup
First system
normal 667 472 1.41 477 331 1.44
async 285 144 1.98 130 14 9.29
sync 768 616 1.25 477 334 1.43
softdep 413 252 1.64 241 38 6.34
Second system
normal 329 81 4.06 263.5 93.5 2.81
async 302 25.7 11.75 112 2.26 49.56
sync 281 57.0 4.93 263 90.5 2.9
softdep 341 40.6 8.4 284 4.76 59.66
"old dirpref" and "new dirpref" columns give a test time in seconds.
speedup - speed increasement in times, ie. old dirpref / new dirpref.
------
Algorithm description
The old dirpref algorithm is described in comments:
/*
* Find a cylinder to place a directory.
*
* The policy implemented by this algorithm is to select from
* among those cylinder groups with above the average number of
* free inodes, the one with the smallest number of directories.
*/
A new directory is allocated in a different cylinder groups than its
parent directory resulting in a directory tree that is spreaded across
all the cylinder groups. This spreading out results in a non-optimal
access to the directories and files. When we have a small filesystem
it is not a problem but when the filesystem is big then perfomance
degradation becomes very apparent.
What I mean by a big file system ?
1. A big filesystem is a filesystem which occupy 20-30 or more percent
of total drive space, i.e. first and last cylinder are physically
located relatively far from each other.
2. It has a relatively large number of cylinder groups, for example
more cylinder groups than 50% of the buffers in the buffer cache.
The first results in long access times, while the second results in
many buffers being used by metadata operations. Such operations use
cylinder group blocks and on-disk inode blocks. The cylinder group
block (fs->fs_cblkno) contains struct cg, inode and block bit maps.
It is 2k in size for the default filesystem parameters. If new and
parent directories are located in different cylinder groups then the
system performs more input/output operations and uses more buffers.
On filesystems with many cylinder groups, lots of cache buffers are
used for metadata operations.
My solution for this problem is very simple. I allocate many directories
in one cylinder group. I also do some things, so that the new allocation
method does not cause excessive fragmentation and all directory inodes
will not be located at a location far from its file's inodes and data.
The algorithm is:
/*
* Find a cylinder group to place a directory.
*
* The policy implemented by this algorithm is to allocate a
* directory inode in the same cylinder group as its parent
* directory, but also to reserve space for its files inodes
* and data. Restrict the number of directories which may be
* allocated one after another in the same cylinder group
* without intervening allocation of files.
*
* If we allocate a first level directory then force allocation
* in another cylinder group.
*/
My early versions of dirpref give me a good results for a wide range of
file operations and different filesystem capacities except one case:
those applications that create their entire directory structure first
and only later fill this structure with files.
My solution for such and similar cases is to limit a number of
directories which may be created one after another in the same cylinder
group without intervening file creations. For this purpose, I allocate
an array of counters at mount time. This array is linked to the superblock
fs->fs_contigdirs[cg]. Each time a directory is created the counter
increases and each time a file is created the counter decreases. A 60Gb
filesystem with 8mb/cg requires 10kb of memory for the counters array.
The maxcontigdirs is a maximum number of directories which may be created
without an intervening file creation. I found in my tests that the best
performance occurs when I restrict the number of directories in one cylinder
group such that all its files may be located in the same cylinder group.
There may be some deterioration in performance if all the file inodes
are in the same cylinder group as its containing directory, but their
data partially resides in a different cylinder group. The maxcontigdirs
value is calculated to try to prevent this condition. Since there is
no way to know how many files and directories will be allocated later
I added two optimization parameters in superblock/tunefs. They are:
int32_t fs_avgfilesize; /* expected average file size */
int32_t fs_avgfpdir; /* expected # of files per directory */
These parameters have reasonable defaults but may be tweeked for special
uses of a filesystem. They are only necessary in rare cases like better
tuning a filesystem being used to store a squid cache.
I have been using this algorithm for about 3 months. I have done
a lot of testing on filesystems with different capacities, average
filesize, average number of files per directory, and so on. I think
this algorithm has no negative impact on filesystem perfomance. It
works better than the default one in all cases. The new dirpref
will greatly improve untarring/removing/coping of big directories,
decrease load on cvs servers and much more. The new dirpref doesn't
speedup a compilation process, but also doesn't slow it down.
Obtained from: Grigoriy Orlov <gluk@ptci.ru>
=====
=====
iedowse 2001/04/23 17:37:17 PDT
Pre-dirpref versions of fsck may zero out the new superblock fields
fs_contigdirs, fs_avgfilesize and fs_avgfpdir. This could cause
panics if these fields were zeroed while a filesystem was mounted
read-only, and then remounted read-write.
Add code to ffs_reload() which copies the fs_contigdirs pointer
from the previous superblock, and reinitialises fs_avgf* if necessary.
Reviewed by: mckusick
=====
=====
nik 2001/04/10 03:36:44 PDT
Add information about the new options to newfs and tunefs which set the
expected average file size and number of files per directory. Could do
with some fleshing out.
=====
2001-09-06 06:16:00 +04:00
|
|
|
.Op Fl g Ar avgfilesize
|
|
|
|
|
.Op Fl h Ar avgfpdir
|
2001-07-29 13:55:22 +04:00
|
|
|
.Op Fl i Ar bytes-per-inode
|
1994-06-08 23:27:32 +04:00
|
|
|
.Op Fl k Ar skew
|
|
|
|
|
.Op Fl l Ar interleave
|
2001-07-29 13:55:22 +04:00
|
|
|
.Op Fl m Ar free-space
|
|
|
|
|
.Op Fl n Ar rotational-positions
|
1994-06-08 23:27:32 +04:00
|
|
|
.Op Fl o Ar optimization
|
2001-07-29 13:55:22 +04:00
|
|
|
.Op Fl p Ar track-spares
|
1994-06-08 23:27:32 +04:00
|
|
|
.Op Fl r Ar revolutions
|
|
|
|
|
.Op Fl s Ar size
|
2001-07-29 13:55:22 +04:00
|
|
|
.Op Fl t Ar ntracks
|
|
|
|
|
.Op Fl u Ar nsectors
|
1994-06-08 23:27:32 +04:00
|
|
|
.Op Fl x Ar sectors
|
1993-03-21 12:45:37 +03:00
|
|
|
.Ar special
|
1993-07-28 04:56:43 +04:00
|
|
|
.Nm mount_mfs
|
1994-06-08 23:27:32 +04:00
|
|
|
.Op Fl N
|
2001-07-29 13:55:22 +04:00
|
|
|
.Op Fl T Ar disk-type
|
1996-12-26 07:37:18 +03:00
|
|
|
.Op Fl a Ar maxcontig
|
1994-06-08 23:27:32 +04:00
|
|
|
.Op Fl b Ar block-size
|
2001-07-29 13:55:22 +04:00
|
|
|
.Op Fl c Ar cpg
|
1994-06-08 23:27:32 +04:00
|
|
|
.Op Fl d Ar rotdelay
|
|
|
|
|
.Op Fl e Ar maxbpg
|
|
|
|
|
.Op Fl f Ar frag-size
|
2001-07-29 13:55:22 +04:00
|
|
|
.Op Fl i Ar bytes-per-inode
|
|
|
|
|
.Op Fl m Ar free-space
|
|
|
|
|
.Op Fl n Ar rotational-positions
|
1994-06-08 23:27:32 +04:00
|
|
|
.Op Fl o Ar options
|
|
|
|
|
.Op Fl s Ar size
|
1993-03-21 12:45:37 +03:00
|
|
|
.Ar special node
|
|
|
|
|
.Sh DESCRIPTION
|
1997-09-15 10:23:03 +04:00
|
|
|
.Nm
|
2001-08-30 12:40:10 +04:00
|
|
|
is used to initialize and clear file systems before first use.
|
1998-04-29 13:49:10 +04:00
|
|
|
Before running
|
1997-09-15 10:23:03 +04:00
|
|
|
.Nm
|
1993-03-21 12:45:37 +03:00
|
|
|
or
|
1993-07-28 04:56:43 +04:00
|
|
|
.Nm mount_mfs ,
|
1998-04-29 13:49:10 +04:00
|
|
|
the disk must be labeled using
|
1993-03-21 12:45:37 +03:00
|
|
|
.Xr disklabel 8 .
|
1997-09-15 10:23:03 +04:00
|
|
|
.Nm
|
1993-03-21 12:45:37 +03:00
|
|
|
builds a file system on the specified special device
|
|
|
|
|
basing its defaults on the information in the disk label.
|
|
|
|
|
Typically the defaults are reasonable, however
|
1997-09-15 10:23:03 +04:00
|
|
|
.Nm
|
1993-03-21 12:45:37 +03:00
|
|
|
has numerous options to allow the defaults to be selectively overridden.
|
|
|
|
|
.Pp
|
1997-09-15 10:23:03 +04:00
|
|
|
.Nm mount_mfs
|
1993-03-21 12:45:37 +03:00
|
|
|
is used to build a file system in virtual memory and then mount it
|
|
|
|
|
on a specified node.
|
1997-09-15 10:23:03 +04:00
|
|
|
.Nm mount_mfs
|
1993-03-21 12:45:37 +03:00
|
|
|
exits and the contents of the file system are lost
|
|
|
|
|
when the file system is unmounted.
|
|
|
|
|
If
|
1993-07-28 04:56:43 +04:00
|
|
|
.Nm mount_mfs
|
1993-03-21 12:45:37 +03:00
|
|
|
is sent a signal while running,
|
|
|
|
|
for example during system shutdown,
|
|
|
|
|
it will attempt to unmount its
|
|
|
|
|
corresponding file system.
|
|
|
|
|
The parameters to
|
1993-07-28 04:56:43 +04:00
|
|
|
.Nm mount_mfs
|
1993-03-21 12:45:37 +03:00
|
|
|
are the same as those to
|
1997-09-15 10:23:03 +04:00
|
|
|
.Nm "" .
|
1997-09-16 18:05:39 +04:00
|
|
|
If the
|
|
|
|
|
.Fl T
|
|
|
|
|
flag is specified (see below), the special file is unused.
|
|
|
|
|
Otherwise, it is only used to read the disk label which provides
|
1993-03-21 12:45:37 +03:00
|
|
|
a set of configuration parameters for the memory based file system.
|
2001-06-07 18:52:50 +04:00
|
|
|
The special file is typically that of the first swap area, since
|
1998-04-29 13:49:10 +04:00
|
|
|
that is where the file system will be backed up when free memory
|
|
|
|
|
gets low and the memory supporting the file system has to be paged.
|
|
|
|
|
If the keyword ``swap'' is used instead of a special file name,
|
|
|
|
|
default configuration parameters will be used.
|
|
|
|
|
(This option is useful when trying to use
|
1994-12-18 09:10:22 +03:00
|
|
|
.Nm mount_mfs
|
1998-04-29 13:49:10 +04:00
|
|
|
on a machine without any disks).
|
1993-03-21 12:45:37 +03:00
|
|
|
.Pp
|
2001-07-29 13:55:22 +04:00
|
|
|
Options with numeric arguments may contain an optional (case-insensitive)
|
|
|
|
|
suffix:
|
|
|
|
|
.Bl -tag -width 3n -offset indent -compact
|
|
|
|
|
.It b
|
|
|
|
|
Bytes; causes no modification. (Default)
|
|
|
|
|
.It k
|
|
|
|
|
Kilo; multiply the argument by 1024
|
|
|
|
|
.It m
|
|
|
|
|
Mega; multiply the argument by 1048576
|
|
|
|
|
.It g
|
|
|
|
|
Giga; multiply the argument by 1073741824
|
|
|
|
|
.El
|
|
|
|
|
.Pp
|
1993-03-21 12:45:37 +03:00
|
|
|
The following options define the general layout policies.
|
|
|
|
|
.Bl -tag -width Fl
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl B Ar byte-order
|
|
|
|
|
Specify the metadata byte order of the file system to be created.
|
1998-04-29 13:49:10 +04:00
|
|
|
Valid byte orders are `be' and `le'.
|
2001-07-29 13:55:22 +04:00
|
|
|
If no byte order is specified, the file system is created in host
|
1998-04-29 13:49:10 +04:00
|
|
|
byte order.
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl F
|
|
|
|
|
Create a file system image in the regular file referenced by
|
|
|
|
|
.Ar special .
|
|
|
|
|
The file system size needs to be specified with
|
|
|
|
|
.Dq Fl s Ar size .
|
1993-03-21 12:45:37 +03:00
|
|
|
.It Fl N
|
|
|
|
|
Causes the file system parameters to be printed out
|
|
|
|
|
without really creating the file system.
|
1994-06-08 23:27:32 +04:00
|
|
|
.It Fl O
|
1998-04-29 13:49:10 +04:00
|
|
|
Creates a
|
1998-02-06 08:54:12 +03:00
|
|
|
.Bx 4.3
|
2001-07-29 13:55:22 +04:00
|
|
|
format file system.
|
|
|
|
|
This option is primarily used to build root file systems
|
1994-06-08 23:27:32 +04:00
|
|
|
that can be understood by older boot ROMs.
|
2001-08-31 12:03:27 +04:00
|
|
|
.It Fl T Ar disk-type
|
1997-09-16 18:05:39 +04:00
|
|
|
Uses information for the specified disk from
|
|
|
|
|
.Pa /etc/disktab
|
|
|
|
|
instead of trying to get the information from a disklabel.
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl Z
|
|
|
|
|
Pre-zeros the file system image created with
|
|
|
|
|
.Fl F .
|
|
|
|
|
This is necessary if the image is to be used by
|
|
|
|
|
.Xr vnd 4
|
|
|
|
|
(which doesn't support file systems with
|
|
|
|
|
.Sq holes ) .
|
1993-03-21 12:45:37 +03:00
|
|
|
.It Fl a Ar maxcontig
|
1994-06-08 23:27:32 +04:00
|
|
|
This specifies the maximum number of contiguous blocks that will be
|
|
|
|
|
laid out before forcing a rotational delay (see the
|
1993-03-21 12:45:37 +03:00
|
|
|
.Fl d
|
1994-06-08 23:27:32 +04:00
|
|
|
option).
|
1994-12-01 21:46:37 +03:00
|
|
|
The default value is 8.
|
1993-03-21 12:45:37 +03:00
|
|
|
See
|
|
|
|
|
.Xr tunefs 8
|
|
|
|
|
for more details on how to set this option.
|
1994-06-08 23:27:32 +04:00
|
|
|
.It Fl b Ar block-size
|
1998-04-29 13:49:10 +04:00
|
|
|
The block size of the file system, in bytes.
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl c Ar cpg
|
1994-06-08 23:27:32 +04:00
|
|
|
The number of cylinders per cylinder group in a file system.
|
|
|
|
|
The default value is 16.
|
1993-03-21 12:45:37 +03:00
|
|
|
.It Fl d Ar rotdelay
|
1994-06-08 23:27:32 +04:00
|
|
|
This specifies the expected time (in milliseconds) to service a transfer
|
|
|
|
|
completion interrupt and initiate a new transfer on the same disk.
|
1994-12-01 21:46:37 +03:00
|
|
|
The default is 0 milliseconds.
|
1993-03-21 12:45:37 +03:00
|
|
|
See
|
|
|
|
|
.Xr tunefs 8
|
|
|
|
|
for more details on how to set this option.
|
1997-09-16 18:05:39 +04:00
|
|
|
.ne 1i
|
1993-03-21 12:45:37 +03:00
|
|
|
.It Fl e Ar maxbpg
|
|
|
|
|
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 another cylinder group.
|
|
|
|
|
The default is about one quarter of the total blocks in a cylinder group.
|
|
|
|
|
See
|
|
|
|
|
.Xr tunefs 8
|
|
|
|
|
for more details on how to set this option.
|
1994-06-08 23:27:32 +04:00
|
|
|
.It Fl f Ar frag-size
|
|
|
|
|
The fragment size of the file system in bytes.
|
Incorporate the enhanced ffs_dirpref() by Grigoriy Orlov, as found in
FreeBSD (three commits; the initial work, man page updates, and a fix
to ffs_reload()), with the following differences:
- Be consistent between newfs(8) and tunefs(8) as to the options which
set and control the tuning parameters for this work (avgfilesize & avgfpdir)
- Use u_int16_t instead of u_int8_t to keep track of the number of
contiguous directories (suggested by Chuck Silvers)
- Work within our FFS_EI framework
- Ensure that fs->fs_maxclusters and fs->fs_contigdirs don't point to
the same area of memory
The new algorithm has a marked performance increase, especially when
performing tasks such as untarring pkgsrc.tar.gz, etc.
The original FreeBSD commit messages are attached:
=====
mckusick 2001/04/10 01:39:00 PDT
Directory layout preference improvements from Grigoriy Orlov <gluk@ptci.ru>.
His description of the problem and solution follow. My own tests show
speedups on typical filesystem intensive workloads of 5% to 12% which
is very impressive considering the small amount of code change involved.
------
One day I noticed that some file operations run much faster on
small file systems then on big ones. I've looked at the ffs
algorithms, thought about them, and redesigned the dirpref algorithm.
First I want to describe the results of my tests. These results are old
and I have improved the algorithm after these tests were done. Nevertheless
they show how big the perfomance speedup may be. I have done two file/directory
intensive tests on a two OpenBSD systems with old and new dirpref algorithm.
The first test is "tar -xzf ports.tar.gz", the second is "rm -rf ports".
The ports.tar.gz file is the ports collection from the OpenBSD 2.8 release.
It contains 6596 directories and 13868 files. The test systems are:
1. Celeron-450, 128Mb, two IDE drives, the system at wd0, file system for
test is at wd1. Size of test file system is 8 Gb, number of cg=991,
size of cg is 8m, block size = 8k, fragment size = 1k OpenBSD-current
from Dec 2000 with BUFCACHEPERCENT=35
2. PIII-600, 128Mb, two IBM DTLA-307045 IDE drives at i815e, the system
at wd0, file system for test is at wd1. Size of test file system is 40 Gb,
number of cg=5324, size of cg is 8m, block size = 8k, fragment size = 1k
OpenBSD-current from Dec 2000 with BUFCACHEPERCENT=50
You can get more info about the test systems and methods at:
http://www.ptci.ru/gluk/dirpref/old/dirpref.html
Test Results
tar -xzf ports.tar.gz rm -rf ports
mode old dirpref new dirpref speedup old dirprefnew dirpref speedup
First system
normal 667 472 1.41 477 331 1.44
async 285 144 1.98 130 14 9.29
sync 768 616 1.25 477 334 1.43
softdep 413 252 1.64 241 38 6.34
Second system
normal 329 81 4.06 263.5 93.5 2.81
async 302 25.7 11.75 112 2.26 49.56
sync 281 57.0 4.93 263 90.5 2.9
softdep 341 40.6 8.4 284 4.76 59.66
"old dirpref" and "new dirpref" columns give a test time in seconds.
speedup - speed increasement in times, ie. old dirpref / new dirpref.
------
Algorithm description
The old dirpref algorithm is described in comments:
/*
* Find a cylinder to place a directory.
*
* The policy implemented by this algorithm is to select from
* among those cylinder groups with above the average number of
* free inodes, the one with the smallest number of directories.
*/
A new directory is allocated in a different cylinder groups than its
parent directory resulting in a directory tree that is spreaded across
all the cylinder groups. This spreading out results in a non-optimal
access to the directories and files. When we have a small filesystem
it is not a problem but when the filesystem is big then perfomance
degradation becomes very apparent.
What I mean by a big file system ?
1. A big filesystem is a filesystem which occupy 20-30 or more percent
of total drive space, i.e. first and last cylinder are physically
located relatively far from each other.
2. It has a relatively large number of cylinder groups, for example
more cylinder groups than 50% of the buffers in the buffer cache.
The first results in long access times, while the second results in
many buffers being used by metadata operations. Such operations use
cylinder group blocks and on-disk inode blocks. The cylinder group
block (fs->fs_cblkno) contains struct cg, inode and block bit maps.
It is 2k in size for the default filesystem parameters. If new and
parent directories are located in different cylinder groups then the
system performs more input/output operations and uses more buffers.
On filesystems with many cylinder groups, lots of cache buffers are
used for metadata operations.
My solution for this problem is very simple. I allocate many directories
in one cylinder group. I also do some things, so that the new allocation
method does not cause excessive fragmentation and all directory inodes
will not be located at a location far from its file's inodes and data.
The algorithm is:
/*
* Find a cylinder group to place a directory.
*
* The policy implemented by this algorithm is to allocate a
* directory inode in the same cylinder group as its parent
* directory, but also to reserve space for its files inodes
* and data. Restrict the number of directories which may be
* allocated one after another in the same cylinder group
* without intervening allocation of files.
*
* If we allocate a first level directory then force allocation
* in another cylinder group.
*/
My early versions of dirpref give me a good results for a wide range of
file operations and different filesystem capacities except one case:
those applications that create their entire directory structure first
and only later fill this structure with files.
My solution for such and similar cases is to limit a number of
directories which may be created one after another in the same cylinder
group without intervening file creations. For this purpose, I allocate
an array of counters at mount time. This array is linked to the superblock
fs->fs_contigdirs[cg]. Each time a directory is created the counter
increases and each time a file is created the counter decreases. A 60Gb
filesystem with 8mb/cg requires 10kb of memory for the counters array.
The maxcontigdirs is a maximum number of directories which may be created
without an intervening file creation. I found in my tests that the best
performance occurs when I restrict the number of directories in one cylinder
group such that all its files may be located in the same cylinder group.
There may be some deterioration in performance if all the file inodes
are in the same cylinder group as its containing directory, but their
data partially resides in a different cylinder group. The maxcontigdirs
value is calculated to try to prevent this condition. Since there is
no way to know how many files and directories will be allocated later
I added two optimization parameters in superblock/tunefs. They are:
int32_t fs_avgfilesize; /* expected average file size */
int32_t fs_avgfpdir; /* expected # of files per directory */
These parameters have reasonable defaults but may be tweeked for special
uses of a filesystem. They are only necessary in rare cases like better
tuning a filesystem being used to store a squid cache.
I have been using this algorithm for about 3 months. I have done
a lot of testing on filesystems with different capacities, average
filesize, average number of files per directory, and so on. I think
this algorithm has no negative impact on filesystem perfomance. It
works better than the default one in all cases. The new dirpref
will greatly improve untarring/removing/coping of big directories,
decrease load on cvs servers and much more. The new dirpref doesn't
speedup a compilation process, but also doesn't slow it down.
Obtained from: Grigoriy Orlov <gluk@ptci.ru>
=====
=====
iedowse 2001/04/23 17:37:17 PDT
Pre-dirpref versions of fsck may zero out the new superblock fields
fs_contigdirs, fs_avgfilesize and fs_avgfpdir. This could cause
panics if these fields were zeroed while a filesystem was mounted
read-only, and then remounted read-write.
Add code to ffs_reload() which copies the fs_contigdirs pointer
from the previous superblock, and reinitialises fs_avgf* if necessary.
Reviewed by: mckusick
=====
=====
nik 2001/04/10 03:36:44 PDT
Add information about the new options to newfs and tunefs which set the
expected average file size and number of files per directory. Could do
with some fleshing out.
=====
2001-09-06 06:16:00 +04:00
|
|
|
.It Fl g Ar avgfilesize
|
|
|
|
|
The expected average file size for the file system.
|
|
|
|
|
.It Fl h Ar avgfpdir
|
|
|
|
|
The expected average number of files per directory on the file system.
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl i Ar bytes-per-inode
|
1993-03-21 12:45:37 +03:00
|
|
|
This specifies the density of inodes in the file system.
|
1996-06-06 19:23:47 +04:00
|
|
|
The default is to create an inode for each 4096 bytes of data space.
|
1993-03-21 12:45:37 +03:00
|
|
|
If fewer inodes are desired, a larger number should be used;
|
|
|
|
|
to create more inodes a smaller number should be given.
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl m Ar free-space
|
1994-06-08 23:27:32 +04:00
|
|
|
The percentage of space reserved from normal users; the minimum free
|
|
|
|
|
space threshold.
|
1996-06-06 19:23:47 +04:00
|
|
|
The default value used is 5%.
|
1994-06-08 23:27:32 +04:00
|
|
|
See
|
|
|
|
|
.Xr tunefs 8
|
|
|
|
|
for more details on how to set this option.
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl n Ar rotational-positions
|
1997-09-16 18:05:39 +04:00
|
|
|
Determines how many rotational time slots there are in
|
|
|
|
|
one revolution of the disk.
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl o Ar optimization
|
|
|
|
|
Optimization preference; either
|
|
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|
|
.Dq space
|
|
|
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|
or
|
|
|
|
|
.Dq time .
|
1994-06-08 23:27:32 +04:00
|
|
|
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.
|
1996-06-06 19:23:47 +04:00
|
|
|
If the value of minfree (see above) is less than 5%,
|
1994-06-08 23:27:32 +04:00
|
|
|
the default is to optimize for space;
|
1996-06-06 19:23:47 +04:00
|
|
|
if the value of minfree is greater than or equal to 5%,
|
1994-06-08 23:27:32 +04:00
|
|
|
the default is to optimize for time.
|
|
|
|
|
See
|
|
|
|
|
.Xr tunefs 8
|
|
|
|
|
for more details on how to set this option.
|
1993-03-21 12:45:37 +03:00
|
|
|
.It Fl s Ar size
|
2001-07-29 13:55:22 +04:00
|
|
|
The size of the file system in sectors.
|
|
|
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|
An
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|
.Sq s
|
|
|
|
|
suffix will be interpreted as the number of sectors (the default).
|
|
|
|
|
All other suffixes are interpreted as per other numeric arguments,
|
|
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|
|
except that the number is converted into sectors by dividing by the
|
|
|
|
|
sector size (as specified by
|
|
|
|
|
.Fl S Ar secsize )
|
|
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|
|
after suffix interpretation.
|
1994-06-08 23:27:32 +04:00
|
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|
.El
|
1993-03-21 12:45:37 +03:00
|
|
|
.Pp
|
1998-04-29 13:49:10 +04:00
|
|
|
The following options override the standard sizes for the disk geometry.
|
1993-03-21 12:45:37 +03:00
|
|
|
Their default values are taken from the disk label.
|
|
|
|
|
Changing these defaults is useful only when using
|
1997-09-15 10:23:03 +04:00
|
|
|
.Nm
|
1994-06-08 23:27:32 +04:00
|
|
|
to build a file system whose raw image will eventually be used on a
|
|
|
|
|
different type of disk than the one on which it is initially created
|
|
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|
|
(for example on a write-once disk).
|
|
|
|
|
Note that changing any of these values from their defaults will make
|
1998-04-29 13:49:10 +04:00
|
|
|
it impossible for
|
|
|
|
|
.Xr fsck_ffs 8
|
1997-03-08 16:47:08 +03:00
|
|
|
to find the alternative superblocks if the standard superblock is lost.
|
1994-06-08 23:27:32 +04:00
|
|
|
.Bl -tag -width Fl
|
1993-03-21 12:45:37 +03:00
|
|
|
.It Fl S Ar sector-size
|
|
|
|
|
The size of a sector in bytes (almost never anything but 512).
|
2001-07-29 13:55:22 +04:00
|
|
|
Defaults to 512.
|
|
|
|
|
.It Fl k Ar skew
|
|
|
|
|
Sector \&0 skew, per track.
|
1994-06-08 23:27:32 +04:00
|
|
|
Used to describe perturbations in the media format to compensate for
|
|
|
|
|
a slow controller.
|
|
|
|
|
Track skew is the offset of sector 0 on track N relative to sector 0
|
|
|
|
|
on track N-1 on the same cylinder.
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl l Ar interleave
|
|
|
|
|
Hardware sector interleave.
|
1994-06-08 23:27:32 +04:00
|
|
|
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:
|
|
|
|
|
.Dl sectors read/sectors passed over
|
|
|
|
|
Thus an interleave of 1/1 implies contiguous layout, while 1/2 implies
|
|
|
|
|
logical sector 0 is separated by one sector from logical sector 1.
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl p Ar track-spares
|
|
|
|
|
Spare sectors per track.
|
1994-06-08 23:27:32 +04:00
|
|
|
Spare sectors (bad sector replacements) are physical sectors that occupy
|
|
|
|
|
space at the end of each track.
|
2001-07-29 13:55:22 +04:00
|
|
|
They are not counted as part of the sectors per track.
|
1993-03-21 12:45:37 +03:00
|
|
|
.Pq Fl u
|
|
|
|
|
since they are not available to the file system for data allocation.
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl r Ar revolutions
|
1994-06-08 23:27:32 +04:00
|
|
|
The speed of the disk in revolutions per minute.
|
1997-09-16 18:05:39 +04:00
|
|
|
.ne 1i
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl t Ar ntracks
|
|
|
|
|
The number of tracks per cylinder available for data allocation by the file
|
1994-06-08 23:27:32 +04:00
|
|
|
system.
|
2001-07-29 13:55:22 +04:00
|
|
|
.It Fl u Ar nsectors
|
1994-06-08 23:27:32 +04:00
|
|
|
The number of sectors per track available for data allocation by the file
|
|
|
|
|
system.
|
|
|
|
|
This does not include sectors reserved at the end of each track for bad
|
|
|
|
|
block replacement (see the
|
|
|
|
|
.Fl p
|
1998-04-29 13:49:10 +04:00
|
|
|
option).
|
2001-08-31 12:03:27 +04:00
|
|
|
.It Fl x Ar spare-sectors-per-cylinder
|
1994-06-08 23:27:32 +04:00
|
|
|
Spare sectors (bad sector replacements) are physical sectors that occupy
|
|
|
|
|
space at the end of the last track in the cylinder.
|
2001-07-29 13:55:22 +04:00
|
|
|
They are deducted from the sectors per track.
|
1993-03-21 12:45:37 +03:00
|
|
|
.Pq Fl u
|
1994-06-08 23:27:32 +04:00
|
|
|
of the last track of each cylinder since they are not available to the file
|
|
|
|
|
system for data allocation.
|
1993-03-21 12:45:37 +03:00
|
|
|
.El
|
1994-06-08 23:27:32 +04:00
|
|
|
.Pp
|
|
|
|
|
The options to the
|
1993-07-28 04:56:43 +04:00
|
|
|
.Nm mount_mfs
|
1994-06-08 23:27:32 +04:00
|
|
|
command are as described for the
|
1997-09-15 10:23:03 +04:00
|
|
|
.Nm
|
1994-06-08 23:27:32 +04:00
|
|
|
command, except for the
|
|
|
|
|
.Fl o
|
|
|
|
|
option.
|
|
|
|
|
.Pp
|
|
|
|
|
That option is as follows:
|
|
|
|
|
.Bl -tag -width indent
|
|
|
|
|
.It Fl o
|
|
|
|
|
Options are specified with a
|
|
|
|
|
.Fl o
|
|
|
|
|
flag followed by a comma separated string of options.
|
|
|
|
|
See the
|
1993-03-21 12:45:37 +03:00
|
|
|
.Xr mount 8
|
1994-06-08 23:27:32 +04:00
|
|
|
man page for possible options and their meanings.
|
1993-03-21 12:45:37 +03:00
|
|
|
.El
|
1999-05-17 00:58:49 +04:00
|
|
|
.Sh NOTES
|
1998-05-07 07:40:48 +04:00
|
|
|
If the file system will be exported over NFS, the
|
|
|
|
|
.Xr fsirand 8
|
|
|
|
|
utility should be run after
|
|
|
|
|
.Nm
|
|
|
|
|
to improve security.
|
1999-03-17 00:52:34 +03:00
|
|
|
.Pp
|
2001-07-29 13:55:22 +04:00
|
|
|
The owner and group ids of the root node of the new file system
|
1999-03-17 00:52:34 +03:00
|
|
|
are set to the effective uid and gid of the user initializing
|
2001-07-29 13:55:22 +04:00
|
|
|
the file system.
|
1999-05-17 00:58:49 +04:00
|
|
|
.Pp
|
|
|
|
|
For the
|
|
|
|
|
.Nm
|
|
|
|
|
command to succeed,
|
2001-04-03 15:21:57 +04:00
|
|
|
the disklabel should first be updated such that the fstype field for the
|
|
|
|
|
partition is set to
|
|
|
|
|
.Bx 4.2 .
|
1993-03-21 12:45:37 +03:00
|
|
|
.Sh SEE ALSO
|
|
|
|
|
.Xr disktab 5 ,
|
|
|
|
|
.Xr fs 5 ,
|
1994-06-08 23:27:32 +04:00
|
|
|
.Xr dumpfs 8 ,
|
1993-03-21 12:45:37 +03:00
|
|
|
.Xr disklabel 8 ,
|
|
|
|
|
.Xr diskpart 8 ,
|
2001-04-03 15:21:57 +04:00
|
|
|
.\" .Xr format 8 ,
|
1998-05-07 07:40:48 +04:00
|
|
|
.Xr fsck_ffs 8 ,
|
|
|
|
|
.Xr fsirand 8 ,
|
1994-06-08 23:27:32 +04:00
|
|
|
.Xr mount 8 ,
|
1993-03-21 12:45:37 +03:00
|
|
|
.Xr tunefs 8
|
|
|
|
|
.Rs
|
|
|
|
|
.%A M. McKusick
|
|
|
|
|
.%A W. Joy
|
|
|
|
|
.%A S. Leffler
|
|
|
|
|
.%A R. Fabry
|
|
|
|
|
.%T A Fast File System for UNIX ,
|
|
|
|
|
.%J ACM Transactions on Computer Systems 2
|
|
|
|
|
.%V 3
|
|
|
|
|
.%P pp 181-197
|
|
|
|
|
.%D August 1984
|
|
|
|
|
.%O (reprinted in the BSD System Manager's Manual)
|
|
|
|
|
.Re
|
|
|
|
|
.Sh HISTORY
|
|
|
|
|
The
|
|
|
|
|
.Nm
|
|
|
|
|
command appeared in
|
|
|
|
|
.Bx 4.2 .
|