cfs – cache file system
cfs –s [–dknrS] [–f partition]
cfs –a netaddr [–dknrS] [–f partition] [mtpt]
cfs –F srvfile [–dknrS] [–f partition] [mtpt]
Cfs is a user–level file server that caches data from remote files
onto a local disk. It is normally started by the kernel at boot
time, though users may start it manually. Cfs is interposed between
the kernel and a network connection to a remote file server to
improve the efficiency of access across slow network
connections such as modem lines. On each open of a file cfs checks
the consistency of cached information and discards any old information
for that file.
Cfs mounts onto mtpt (default /) after connecting to the file server.
The options are:
n mount the remote file server without authentication; often useful with –F.
r reformat the cache disk partition.
s the connection to the remote file server is on file descriptors 0 and 1.
S turn on statistics gathering. A file called cfsctl at the root of the caching file system can be read to get statistics concerning number of calls/bytes on client and server sides and latencies.
All 9P messages except read, clone, and walk (see intro(5)) are
passed through cfs unchanged to the remote server. If possible,
a read is satisfied by cached data. Otherwise, the file server
is queried for any missing data.