sm-notify(8)

NAME
sm-notify - Send out NSM reboot notifications

SYNOPSIS
/sbin/sm-notify [-d] [-q] [-m time]

DESCRIPTION
File locking over NFS requires a facility to notify peers in case of a reboot, so that clients can reclaim locks after a server crash, and/or servers can release locks held by the rebooted client.

This is a two-step process: during normal operations, a mechanism is required to keep track of which hosts need to be informed of a reboot. And of course, notifications need to be sent out during reboot. The protocol used for this is called NSM, for Network Status Monitor.

Commonly, these two features are provided by the rpc.statd daemon. The SuSE Linux Kernel includes a kernel level implementation of statd, which keeps track of the hosts that need notifications, and accepts reboot notifications.

This is complemented by the sm-notify application, which is responsible for sending out the reboot notifications.

  Operation
For each NFS client or server machine to be monitored, the kernel level statd creates a file in /var/lib/nfs/sm, and removes the file if monitoring is no longer required.

When the machine is rebooted, sm-notify iterates through these files and notifies the peer statd server on those machines.

Each machine has an NSM state , which is basically an integer counter that is incremented each time the machine reboots. This counter is stored in /var/lib/nfs/state, and updated by sm-notify.

OPTIONS

-m failtime
    When notifying hosts, sm-notify will try to contact each host for up to 15 minutes, and will give up if unable to reach it within this time frame.

    Using the -m option, you can override this. A value of 0 tells sm-notify to retry indefinitely; any other value is interpreted as the maximum retry time in minutes.

-q  Be quiet. This suppresses all messages except error messages while collecting the list of hosts.

-n  Do not update the NSM state. This is for testing only.

-d  Enables debugging. By default, sm-notify forks and puts itself in the background after obtaining the list of hosts from /var/lib/nfs/sm.

FILES
/var/lib/nfs/state
/var/lib/nfs/sm/*
/var/lib/nfs/sm.bak/*

SEE ALSO
rpc.nfsd(8), portmap(8)

AUTHORS
Olaf Kirch <okir@suse.de>