fstab.5

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)fstab.5	8.1	9/11/90
.TH fstab 5 
.SH Name
fstab \- file containing static information about known file systems
.SH Description
.NXR "fstab file" "format"
.NXR "file system" "getting information"
.NXAM "quotacheck command" "fstab file"
.NXAM "swapon command" "fstab file"
.NXAM "dump command" "fstab file"
.NXAM "fsck command" "fstab file"
.NXAM "mount command (general)" "fstab file"
.NXR "fstab file" "mounting file systems"
The 
.PN /etc/fstab
file contains descriptive information about the known file
systems.
By convention, 
.PN /etc/fstab
is created and maintained as a read-only
file by the system administrator.
Each file system is described by its own line within 
.PN /etc/fstab .
The order of these lines and the file systems they represent
is important because
.PN fsck
and
.PN mount 
sequentially process 
.PN /etc/fstab
in the performance of their tasks.
.PP
The format of each file system description in 
.PN /etc/fstab
is as follows:
.EX
spec:file:type:freq:passno:name:options
.EE
The meanings of these fields are:
.IP spec 10
The block special file name of the device on which the file 
system is located.  It can also be a network name for 
.PN nfs ,
such as 
.PN /@erie 
or 
.PN /@suez .
.IP file
The pathname of the directory on which the file system is mounted.
.IP type
How the file system is mounted.  The ways in which a file
system can be mounted are:
.br 
rw - mount the file system read-write
.br
ro - mount the file system read only 
.br
rq - mount the file system read-write with quotas
.br
sw - make the special file part of the swap space
.br
xx - ignore the entry
.IP freq
The frequency (in days) with which the
.PN dump
command dumps the rw, ro, and rq file systems.
.IP passno
The order in which the
.PN fsck
command checks the rw, ro, and rq file systems
at reboot time.
.IP name
The name of the file system type.
File systems can have the following
types:
ufs -- ULTRIX file system and
nfs -- SUN Network file system.
.IP options
The options field.  This field contains an arbitrary string
meaningful only when mounting file systems with the specified
file system type name, such as NFS.
The specific options are described in the
.PN mount
reference pages.
.PP
Special actions occur for file systems of type sw and rq at
system boot time.
File systems of type sw are made part of the swap space by the
.MS swapon 8
command and
disk quotas are automatically processed by the 
.MS quotacheck 8
command and then enabled by the 
.MS quotaon 8
command for rq file
systems. 
.SH Examples
.NXR(e) "fstab file"
Here is a sample
.PN fstab
file:
.EX 0
/dev/ra0a:/:rw:1:1:ufs::
/dev/ra1g:/usr:rw:1:2:ufs::
/@bigvax:/bigvax:rw:0:0:nfs::
/usr/uws2.0@bigvax:/usr/uws2.0:rw:0:0:nfs:soft,bg,nosuid:
/usr/dec@bigvax:/usr/dec:rw:0:0:nfs:bg,soft,nosuid:
/usr/pro/xyz@vax:/usr/pro/xyz:rw:0:0:nfs:bg,soft,intr,nosuid:
.EE
The last three entries in the
.PN fstab
sample shown use NFS options as described in the
.MS mount 8nfs
reference page.
.SH Restrictions
.NXR "fstab file" "restricted"
The passno field of the root file system should be specified 
as 1.  Other file systems should have larger values.  File 
systems on the same device should have distinct passno fields.
File systems on different devices may have the identical passno
fields to allow them to be simultaneously checked.
.PP
All field delimiters (:) must exist within each file system description;
only the options field may not be present.  However,
only the fields spec and type are meaningful to sw file systems and
only the type field is meaningful to xx file systems.
.PP
The file system description within 
.PN /etc/fstab
should be parsed
only through use of the
.PN getfsent
routines.
.SH Files
.TP 15
.PN /etc/fstab
File system information file
.SH See Also
getfsent(3x), dump(8), fsck(8), mount(8), mount(8nfs), mount(8ufs)
quotacheck(8), quotaon(8), swapon(8)