FILESYSTEMS(5,F) AIX Technical Reference FILESYSTEMS(5,F)
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filesystems
PURPOSE
Centralizes file system characteristics.
DESCRIPTION
A file system is a complete directory structure, including a root directory and
any directories and files beneath it. A file system is confined to a single
partition. All of the information about the file system is centralized in the
filesystems file. Most of the file system maintenance commands take their
defaults from this file. The file is organized into stanzas whose names are
file system names and whose contents are attribute-value pairs specifying
characteristics of the file system.
The filesystems file serves two purposes:
o It documents the layout characteristics of the file systems.
o It frees the person who sets up the file system from having to enter and
remember items such as the device where the file system resides because
this information is defined in the file.
If the Transparent Computing Facility is installed, there is a unique
/etc/filesystems for each cluster site (/etc/filesystems is a symbolic link
into the local file system).
File System Attributes
Each stanza names the directory (which must be the full pathname) where the
file system is normally mounted. The attributes specify all of the parameters
of the file system. See "attributes" for the format of an attribute file. The
attributes currently used are:
account Used by the dodisk command to determine the file systems to be
processed by the accounting system. This value can be either TRUE
or FALSE.
backupden Used by the backup command to determine the density of the default
backup device associated with each file system. Density is
measured in bytes per inch. The parameter is ignored for
diskettes.
backupdev Used by the backup and restore commands to determine the default
output device associated with each file system. The value of this
keyword is usually the name of a diskette or magnetic tape special
file.
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backuplen Used by the backup command to determine the size of the default
backup device associated with each file system. The size of a
tape is measured in tracks times feet. For example, the backuplen
for a 300-foot 9-track tape is 2700. This parameter is ignored
for diskettes.
backuplev Used by the backup command to determine the default backup level
to take for each file system. Backup levels are discussed in the
backup command.
bad List of physically flawed disk blocks which are excluded from the
pool of available file system blocks.
boot Used by the mkfs command to initialize the boot block of a new
file system. This specifies the name of the load module to be
placed into the first block of the file system.
check Used by the fsck command to determine the default file systems to
be checked. TRUE enables checking while FALSE disables checking.
If a number, rather than TRUE is specified, the number indicates
which of multiple concurrent fsck processes will check this file
system. This parallel checking, described in fsck command in AIX
Operating System Commands Reference, permits multiple file systems
to be checked in parallel when multiple drives exist.
cyl Used by the mkfs command to initialize the free list and super
block of a new file system. The value is the number of blocks in
one cylinder. It defines the size of an interleave cluster.
dev Identifies, for local mounts, the block special file where the
file system resides. System management utilities use this
attribute to map file system names to the corresponding device
names. For NFS mounts, the host:NFSdir form is used. Host
specifies the host machine on which the remote file system
resides. NFSdir specifies the path name of the remote file system
being mounted. Use ASCII characters for filesystem name to ensure
successful communication across different locales.
free Used by the df command to determine which file systems are to have
their free space displayed by default. This value is either TRUE
or FALSE.
freq Used by the dumpbsd command, freq specifies dump frequency,
indicated by number of days.
ftype File system type. May include one of the following values:
nfs An NFS mounted file system.
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nonrepl A standard file system which is not replicated on
other sites. This filesystem is accessible by other
sites in a TCF cluster only when the machine storing
it is up.
repl A filesystem which is one instance of multiple copies
throughout a TCF cluster. The following value is
used to differentiate between system and user
replicated file systems:
user This filesystem is user replicated. If
this value is not present, the file
system is system replicated.
One of the following may also be present:
primary This is the primary copy of the
replicated file system, readable and
writable by all sites in the TCF cluster.
backbone A backup copy of a replicated filesystem,
readable by all sites, but writable only
by the primary site.
System replicated filesystems which are not primary
or backbone must include the following:
fstore An fstore value found in /ect/fstore
which indicates what files are present on
this secondary copy.
gfs Global file system number. Used by TCF. Every minidisk on a node
has a different gfs number.
gfspack Global file system. Always 1 for nonreplicated file systems.
Used by TCF.
inodes Used by the mkfs command for reference and to build the file
system. The value is the number of inodes (files) in the file
system. If this attribute is not specified, the value is
calculated from the size attribute.
mode Used by the dumpbsd command, mode specifies the type of file
system desired, as follows:
rw Read/write device
ro Read only device
sw Swap device
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nm File system normally not mounted
xx Ignore type.
mount Used by the mount command to determine whether or not this file
system should be mounted by default. The possible values of mount
are:
automatic Automatically mounts a filesystem when the system is
rebooted. For example, in the sample file, the root
file system is mount=automatic. This means the root
file system mounts automatically when the system is
rebooted. The TRUE value is not used so that mount all
does not try to mount it. Also, the value is not FALSE
because certain utilities, such as ncheck normally
avoid file systems with a value of mount=false.
false This file system is not mounted by default.
true This file system is mounted by the mount all (or mount
-a) command.
After a value of true or false, the following can be specified:
readonly The filesystem is mount read-only by default.
options See -o options in the MOUNT command in AIX Operating System
Commands Reference.
site The name of the machine that contains the minidisk.
size Used by the mkfs command for reference and to build the file
system. The value is the number of blocks in the file system.
skip Used by the mkfs command to initialize the free list and super
block of a new file system. The value is the number of blocks to
skip when the free list is interleaved. This number is processor-
and device-specific.
type Used by the mount command to determine whether or not this file
system should be mounted. When the command "mount -t" string is
issued, all of the currently unmounted file systems with a type
equal to string are mounted.
vol Used by the mkfs command when initializing the label on a new file
system. The value is a volume or pack label using a maximum of
eight characters. The file system label is always the stanza
name.
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quotas Used to mark which file system will be affected when a -a flag is
specified with a quotaon, quotaoff, quotacheck, or repquota
command. If the value is "on", the file system is affected.
Otherwise, it is ignored.
EXAMPLE
*
* File system information
*
default:
vol = "AIX"
mount = false
check = false
free = false
backupdev =/dev/fd0
backuplen = 1440
/u1:
dev = /dev/hd1
vol = "/u1"
mount = true
check = 1
gfs = 2
gfspack = 1
size = 12000
ftype = nonrepl
free = true
site = aixps
/aixps:
dev = /dev/hd2
vol = "/aixps"
mount = automatic
check = 0
gfs = 3
gfspack = 1
size = 6000
ftype = nonrepl
free = true
site = aixps
/:
dev = /dev/hd3
vol = "/"
mount = automatic
check = 0
gfs = 1
gfspack = 1
size = 50000
ftype = repl,primary
free = true
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site = aixps
*
/aixps/tmp:
dev = /dev/hd6
vol = "/aixps/tmp"
mount = true
check = 1
gfs = 4
gfspack = 1
size = 4000
ftype = nonrepl
free = true
site = aixps
*
/ul/aixps2:
dev = "aixps2:/ul"
vol = "/ul/aixps2"
options = "rw,intr,bg"
gfs = 101
mount = false
checks = false
free = true
type = nfs_mount
ftype = nfs
site = aixps
FILE
/etc/filesystems
RELATED INFORMATION
In this book: "attributes" and "fs."
The backup, df, dumpbsd, fsck, mkfs, mount, restore, and umount commands in AIX
Operating System Commands Reference.
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