NAME

Net::CascadeCopy - efficiently replicate files across many servers

SYNOPSIS

    use Net::CascadeCopy;

    # create a new CascadeCopy object
    my $ccp = Net::CascadeCopy->new( { ssh          => "/path/to/ssh",
                                       ssh_flags    => "-x -A",
                                       max_failures => 3,
                                       max_forks    => 2,
                                   } );

    # set the command and arguments to use to transfer file(s)
    $ccp->set_command( { command => "scp",
                         args    => "-p",
                     } );

    # set path on the local server
    $ccp->set_source_path( "/path/on/local/server" );
    # set path on all remote servers
    $ccp->set_source_path( "/path/on/remote/servers" );

    # add lists of servers in multiple datacenters
    $ccp->add_group( "datacenter1", \@dc1_servers );
    $ccp->add_group( "datacenter2", \@dc2_servers );

    # transfer all files
    $ccp->transfer();

DESCRIPTION

This module efficiently replicates a file or directory across a large number of servers in multiple datacenters via rsync or scp.

The usual approach to copying a file to many servers is to copy it to one or more central file servers and then copy it from there to every other server in the datacenter. The speed at which the file can be copied is a function of the local cpu/disk utilization and the network throughput on the file server(s).

This module takes a different approach. Once a file has been copied to a remote server, that server will then be used as a source point for copying the file to additional servers.

CONSTRUCTOR

new( )

Returns a reference to a new use Net::CascadeCopy object.

This is an inside-out perl class. For more info, see "Perl Best Practices" by Damian Conway

INTERFACE

$self-add_group( $groupname, \@servers )>

Add a group of servers. Ideally all servers will be located in the same datacenter. This may be called multiple times with different group names to create multiple groups.

$self-set_command( $command, $args )>

Set the command and arguments that will be used to transfer files. For example, "rsync" and "-ravuz" could be used for rsync, or "scp" and "-p" could be used for scp.

$self-set_source_path( $path )>

Specify the path on the local server where the source files reside.

$self-set_target_path( $path )>

Specify the target path on the remote servers where the files should be copied.

$self-transfer( )>

Transfer all files. Will not return until all files are transferred.

BUGS AND LIMITATIONS

There are no known bugs in this module. Please report problems to VVu@geekfarm.org

Patches are welcome.

AUTHOR

Alex White <vvu@geekfarm.org>

LICENCE AND COPYRIGHT

Copyright (c) 2007, Alex White <vvu@geekfarm.org>. All rights reserved.

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

- Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

- Neither the name of the geekfarm.org nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.