lamshrink - Online in the Cloud

This is the command lamshrink that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

PROGRAM:

NAME


lamshrink - Shrink a LAM universe.

SYNOPSIS


lamshrink [-dhv] [-w delay] nodeid

OPTIONS


-d Print detailed debugging information.

-h Print useful information on this command.

-v Be verbose.

-w delay Notify processes on the doomed node and pause for delay seconds before
proceeding.

nodeid Remove the LAM node with this ID.

DESCRIPTION


An existing LAM session, initiated by lamboot(1), can be shrunk to include less nodes with
lamshrink. One node is removed for each invocation. At a minimum, the node ID is given
on the command line. Once lamshrink completes, the node ID is invalid across the
remaining nodes (as can be seen by running lamnodes(1)).

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 lamshrink 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.

FAULT TOLERANCE
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 lamshrink after the warning step. In
particular, the SIGSHRINK signal is delivered.

EXAMPLES


lamshrink -v n1 Remove LAM on n1. Report about important steps as
they are done.

lamshrink n30 -w 10
Inform all processes on LAM node 30, that the node will be dead in 10 seconds. Wait
10 seconds and remove the node. Operate silently.

Use lamshrink online using onworks.net services



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