mount_cachefs(1M) manual page
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mount_cachefs - mount CacheFS file systems
mount -F cachefs
[ generic_options ] -o backfstype=file_system_type [ other cacheFS options]
special mount_point
SUNWcsu
The CacheFS-specific
version of the mount command mounts a cached file system; if necessary,
it NFS-mounts its back file system. It also provides a number of CacheFS-specific
options for controlling the caching process. For more information regarding
back file systems, refer to the
To mount a CacheFS file system,
use the generic mount command with the -F option followed by the argument
cachefs. The following generic mount options are available:
- -m
- Mount the
file system without making an entry in the /etc/mnttab file.
- -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.
- -r
- Mount the file system read-only.
The following arguments to the -o option are specifically for CacheFS mounts.
Use commas to separate multiple options. Note: the backfstype argument
must be specified.
- backfstype=file_system_type
- The file system type of
the back file system (for example, nfs).
- 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.
- 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.
- noconst
- Disables cache consistency checking. By default, periodic consistency
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.
- 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 systems 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 or having the back file system verify access
permissions. Do not use this argument with secure NFS
.
- purge
- Purge any cached
information for the specified file system.
- rw | ro
- Read-write (default) or
read-only.
- suid | nosuid
- Allow (default) or disallow set-uid execution.
- acregmin=n
- Specifies that cached attributes are held for at least n seconds 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.
- 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.
- acdirmin=n
- Specifies that cached attributes are held
for at least n seconds 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.
- 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.
- actimeo=n
- Sets acregmin, acregmax, acdirmin, and acdirmax to
n.
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
cfsadmin(1M)
, fsck_cachefs(1M)
, mount(1M)
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