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
[specific_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
.
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 spa‐
ces.
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 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.
acregmax=n
Specifies that cached attributes are held
for no more than n seconds after file modi‐
fication. After n seconds, all file informa‐
tion is purged from the cache. The default
value is 30 seconds.
acregmin=n
Specifies that cached attributes are held
for at least n seconds after file modifica‐
tion. 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 sys‐
tem 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 explic‐
itly requested, rather than the periodic
checking that is done by default. A consis‐
tency 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/open‐
win. 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 consistency checking is
enabled. Specify noconst only when you know
that the back file system will not be modi‐
fied. 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 sys‐
tem. 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 with‐
out 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 │SUNWcs │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOcfsadmin(1M), fsck_cachefs(1M), mount(1M), attributes(5)BUGS
The output for the generic_option -p output is incorrect for cachefs.
SunOS 5.11 18 Mar 2004 mount_cachefs(1M)
