NAME
lockd: rpc.lockd — network lock daemon
SYNOPSIS
/usr/sbin/rpc.lockd
[-g
graceperiod]
[-l
listen_min_backlog]
[-t
timeout]
[nthreads]
DESCRIPTION
The
lockd
utility is part of the NFS lock manager, which supports record lock and
share lock operations on NFS files.
See
fcntl(2)
and
lockf(2).
lockd
provides two functions:
It forwards
fcntl(2)
locking requests for NFS mounted file systems to the
lockd
on the NFS server.
It generates local file locking operations in response to
requests forwarded from
lockd
running on NFS client machines.
State information kept by the
lockd
about these locking requests can be lost if
lockd
is killed or the operating system is rebooted.
Some of this information can be recovered as follows.
When a server recovers, it waits for a grace period for all NFS client-site
lockd
to submit reclaim requests.
Client-site
lockd
is notified by the
statd(1M)
of the server recovery, and promptly resubmits previously granted
lock requests.
If a
lockd
fails to secure a previously granted lock at the server site, then the
lockd
sends a
SIGLOST
to the process holding that lock.
Administrators can make changes to the startup parameters for
lockd
by logging in as root and editing the
/etc/default/nfs
file (see
nfs(4)).
Administrators can also make changes by using the
setoncenv
command.
Options
lockd
recognizes the following options and command-line arguments:
- -g graceperiod
Deprecated in favor of the
LOCKD_GRACE_PERIOD
parameter in the NFS default file, which is equivalent.
Specify the number of seconds that all clients (both NLM and NFSv4)
have to reclaim locks after the server reboots.
This option also controls the NFSv4 lease interval.
The default value is 90 seconds.
- -l listen_min_backlog
Specify the listener backlog,
listen_min_backlog,
which is the number of connect requests that are queued and waiting
to be processed before new connect requests begin to get dropped.
- -t timeout
Specify the number of seconds to wait before retransmitting a lock
request to the remote server.
The default value is 5 seconds.
Equivalent to the
LOCKD_RETRANSMIT_TIMEOUT
parameter in the NFS default file.
- nthreads
Specify the maximum number of concurrent threads that the server can handle.
This concurrency is achieved by up to
nthreads
threads created as needed in the kernel.
nthreads
should be based on the load expected on this server.
If
nthreads
is not specified, the maximum number of concurrent threads will default to 20.
Equivalent to the
LOCKD_SERVERS
parameter in the NFS default file.
Notes
A directory service that provides service name data base support must have
the following service entries in its database:
lockd 4045/udp # NFS lockd daemon/manager for udp
lockd 4045/tcp # NFS lockd daemon/manager for tcp
AUTHOR
lockd
was developed by Sun Microsystems, Inc. and HP.
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