CFS(4)

NAME

cfs − cache file system

SYNOPSIS

cfs -s [-rdS] [-f partition]

cfs -a netaddr [-rdS] [-f partition] [mtpt]

DESCRIPTION

Cfs is a user-level file server that caches information about 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:

s the connection to the remote file server is on file descriptors 0 and 1.

a netaddr
dial the destination netaddr to connect to a remote file server.

r reformat the cache disk partition.

d turn on debugging.

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.

f partition
use file partition as the cache disk partition.

All 9P messages except read, clone, and walk (see intro(5)) are passed through cfs unchanged to the remote server. A clone followed immediately by a walk is converted into a clwalk. 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