mount_cachefs(1M) System Administration Commands mount_cachefs(1M)NAMEmount_cachefs - mount CacheFS file systems
SYNOPSIS
mount -F cachefs [generic_options] -o backfstype=file_system_type [spe‐
cific_options] [-O] special mount_point
DESCRIPTION
The CacheFS-specific version of the mount command mounts a cached file
system; if necessary, it NFS-mounts its back file system. It also pro‐
vides a number of CacheFS-specific options for controlling the caching
process. For more information regarding back file systems, refer to the
System Administration Guide: Basic Administration.
mount_cachefs cannot be used with replicated NFS mounts. mount_cachefs
creates a pass through when used with an NFS version 4 mount. No
caching is performed.
OPTIONS
To mount a CacheFS file system, use the generic mount command with the
-F option followed by the argument cachefs.
See mount(1M) for a list of supported generic_options.
-o specific_options
Specify CacheFS file system specific options in a comma-separated
list with no intervening spaces.
acdirmax=n
Specifies that cached attributes are held for no more than n
seconds after directory update. After n seconds, all directory
information is purged from the cache. The default value is 30
seconds.
acdirmin=n
Specifies that cached attributes are held for at least n sec‐
onds after directory update. After n seconds, CacheFS checks to
see if the directory modification time on the back file system
has changed. If it has, all information about the directory is
purged from the cache and new data is retrieved from the back
file system. The default value is 30 seconds.
acregmax=n
Specifies that cached attributes are held for no more than n
seconds after file modification. After n seconds, all file
information is purged from the cache. The default value is 30
seconds.
acregmin=n
Specifies that cached attributes are held for at least n sec‐
onds after file modification. After n seconds, CacheFS checks
to see if the file modification time on the back file system
has changed. If it has, all information about the file is
purged from the cache and new data is retrieved from the back
file system. The default value is 30 seconds.
actimeo=n
Sets acregmin, acregmax, acdirmin, and acdirmax to n.
backfstype=file_system_type
The file system type of the back file system (can be nfs or
hsfs).
backpath=path
Specifies where the back file system is already mounted. If
this argument is not supplied, CacheFS determines a mount point
for the back file system. The back file system must be read-
only.
cachedir=directory
The name of the cache directory.
cacheid=ID
ID is a string specifying a particular instance of a cache. If
you do not specify a cache ID, CacheFS will construct one.
demandconst
Verifies cache consistency only when explicitly requested,
rather than the periodic checking that is done by default. A
consistency check is requested by using the -s option of the
cfsadmin(1M) command. This option is useful for back file sys‐
tems that change infrequently, for example, /usr/openwin.
demandconst and noconst are mutually exclusive.
local-access
Causes the front file system to interpret the mode bits used
for access checking instead of having the back file system ver‐
ify access permissions. Do not use this argument with secure
NFS.
noconst
Disables cache consistency checking. By default, periodic con‐
sistency checking is enabled. Specify noconst only when you
know that the back file system will not be modified. Trying to
perform cache consistency check using cfsadmin -s will result
in error. demandconst and noconst are mutually exclusive.
write-around | non-shared
Write modes for CacheFS. The write-around mode (the default)
handles writes the same as NFS does; that is, writes are made
to the back file system, and the affected file is purged from
the cache. You can use the non-shared mode when you are sure
that no one else will be writing to the cached file system. In
this mode, all writes are made to both the front and the back
file system, and the file remains in the cache.
-O
Overlay mount. Allows the filesystem to be mounted over an existing
mount point, making the underlying filesystem inaccessible. If a
mount is attempted on a pre-existing mount point without setting
this flag, mount will fail with the error:
mount -F cachefs: mount failed Device busy.
EXAMPLES
Example 1: CacheFS-mounting a File System
The following example CacheFS-mounts the file system server1:/user2,
which is already NFS-mounted on /usr/abc as /xyz.
example# mount -F cachefs -o backfstype=nfs,backpath=/usr/abc,
cachedir=/cache1 server1:/user2 /xyz
The lines similar to the following appear in the /etc/mnttab file after
the mount command is executed:
server1:/user2 /usr/abc nfs
/usr/abc /cache1/xyz cachefs backfstype=nfs
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWcsu │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOcfsadmin(1M), fsck_cachefs(1M), mount(1M), attributes(5) System Admin‐
istration Guide: Basic Administration
BUGS
The output for the generic_option -p output is incorrect for cachefs.
SunOS 5.10 18 Mar 2004 mount_cachefs(1M)
