NFS Services Administrator's Guide HP-UX 11i version 3

The functionality provided by this command is an alternative to the rpages mount option.
For information on how to pre-load or pack files, see “Packing a Cached Filesystem”
(page 87).
• Complete Binary Caching via the “rpages” mount option
CacheFS is commonly used to manage application binaries. The rpages mount option forces
the client to cache a complete copy of the accessed application binary file. Whenever an
application in a cached NFS filesystem is executed, CacheFS checks if the binary file exists
in the local cache. If it does not exist, the client reads the entire binary file and automatically
caches the binary file. If the client reads only a part of the binary file, the entire binary is
automatically cached. For information on how to cache a complete binary, see “Caching a
Complete Binary” (page 87).
• Multiple CacheFS Write Modes
CacheFS supports two write modes, write-around and non-shared. In the
write-around mode, writes are made to the back filesystem and the affected file is purged
from the cache.
You can use the non-shared mode to write to both the front and the back filesystems. All
writes are made to both the front and the back filesystem and the file remains in the cache.
To change the CacheFS write mode from write-around to the non-shared, you have to
first unmount the CacheFS filesystem and then mount it using the non-shared option.
• Multiple Cache Consistency Checking Modes
CacheFS periodically checks the files that are stored in the cache to ensure that the data in
these files are kept up to date. CacheFS provides different consistency checking modes,
including:
— demandconst
Verifies or checks for consistency on demand or only when explicitly requested.
NOTE: For information on how to force a cache consistency check, see “Forcing a
Cache Consistency Check” (page 89).
— noconst
Disables consistency checking. Use this option only if you know that the contents of
the back filesystem are rarely modified.
— weakconst
Verifies cache consistency with the NFS client's copy of the file attributes.
NOTE: Consistency is not checked at file open time.
• Switching Mount Options
You can also switch between mount options without deleting or rebuilding the cache. For
example, you can switch from default to non-shared, or from noconst to demandconst
mount options without recreating the cache. For information on how to switch mount options,
see “Switching Mount Options” (page 85).
• Support for Large Files and Large Filesystems
CacheFS supports the maximum file and filesystem sizes supported by the underlying front
filesystem and the back filesystem.
CacheFS data structures are 64-bit compliant.
Features of CacheFS 83