NFS Services Administrator's Guide (B.11.31.03) August 2008

Features of CacheFS
This section discusses the features that CacheFS supports on systems running HP-UX
11i v3.
Cache Pre-Loading via the “cachefspack” Command
The cachefspack command enables you to pre-load or pack specific files and
directories in the cache, thereby improving the effectiveness of CacheFS. It also
ensures that current copies of these files are always available in the cache. Packing
files and directories in the cache enables you to have greater control over the cache
contents.
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 118).
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 118).
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.
112 Configuring and Administering a Cache Filesystem