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>> lamshrink (1) ( Linux man: Команды и прикладные программы пользовательского уровня )
lamshrink - Shrink a LAM multicomputer.
- lamshrink [-hv] [-w <delay>] [-u <userid>] <node> <hostname>
Print useful information on this command.
Remove the LAM node on this host.
Remove the LAM node with this ID.
- -w <delay>
Notify processes on the doomed node and pause for <delay> seconds
- -u <userid>
Use this userid to access the host.
An existing LAM session, initiated by lamboot
(1), can be shrunk to
include less nodes with
One node is removed for each invocation.
At a minimum, the node ID and the associated host name is given on
the command line.
completes, the node ID is invalid across the remaining nodes.
If a different userid is required to access the host, it is specified
with the -u option.
Existing application processes on the target node can be warned
of impending shutdown with the -w option.
A LAM signal (SIGFUSE) will be sent to these processes and
will then pause for the given number of seconds before proceeding
with removing the node.
By default, SIGFUSE is ignored.
A different handler can be installed with ksignal(2).
All application processes on all remaining nodes are always informed
of the death of a node.
This is also done with a signal (SIGSHRINK), which by default causes
a process's runtime route cache to be flushed (to remove any cached
information on the dead node).
If this signal is re-vectored for the purpose of fault tolerance, the
old handler should be called at the beginning of the new handler.
The signal does not, by itself, give the process information on which
node has been removed.
One technique for getting this information is to query the router
for information on all relevant nodes using getroute(2).
The dead node will cause this routine to return an error.
If enabled with lamboot
(1), LAM will watch for nodes that fail.
The procedure for removing a node that has failed is the same as
after the warning step.
In particular, the SIGSHRINK signal is delivered.
- lamshrink -v newhost n1
Remove LAM on newhost, known within LAM as node 1.
Report about important steps as they are done.
- lamshrink newhost n30 -w 10
Inform all processes on LAM node 30, which is running on newhost,
that the node will be dead in 10 seconds.
Wait 10 seconds and remove the node.
- FAULT TOLERANCE
- SEE ALSO