CFS(4) CFS(4)
NAME
cfs - cache file system
SYNOPSIS
cfs -s [-dknrS] [-f partition]
cfs -a netaddr [-dknrS] [-f partition] [mtpt]
cfs -F srvfile [-dknrS] [-f partition] [mtpt]
DESCRIPTION
Cfs is a user-level file server that caches data from remote
files onto a local disk. It is normally started by the ker-
nel 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:
a netaddr
dial the destination netaddr to connect to a remote file
server. Exclusive with -F.
d turn on debugging.
f partition
use file partition as the cache disk partition.
F srvfile
open srvfile (often a file under /srv) to connect to a
remote file server. Exclusive with -a.
k keep cache contents even if they might have come from a
different server. Cfs will obey -r even if -k is given.
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.
Page 1 Plan 9 (printed 12/21/24)
CFS(4) CFS(4)
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.
FILES
/dev/sdC0/cache
Default file used for storing cached data.
SOURCE
/sys/src/cmd/cfs
Page 2 Plan 9 (printed 12/21/24)