Resolving multiple master node conflict in a DDB

• US 7,730,180 B1
• Filed: 07/20/2007
• Issued: 06/01/2010
• Est. Priority Date: 09/27/2001
• Status: Expired due to Fees

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Krishnan, Sriram, Lazar, Gregory W.
• Primary Examiner(s): Bruckart; Benjamin R
• Assistant Examiner(s): Baturay; Alicia
• Application Number:
  US11/880,325
• Time in Patent Office: 1,047 Days
• Field of Search: 709/224
• US Class Current: 709/224
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor

Abstract

In a multinode computer network, a directory database (DDB) in each of the nodes, contents of the DDB being replicated throughout the network through use of one of its nodes having been appointed as master node. The master node updates each DDB in each node in its network or domain configuration when the configuration changes. A global administrator has authority to replace or select a master node and to configure a domain, and performs these and other functions by way of computer terminal screen dialogs offered by a graphical user interface (GUI) associated with the computer network. In the case of multiple master nodes attempting to be master for the same nodes in the same network at the same time, this conflict is resolved in one embodiment of the present invention by allowing the most recently selected purported master node to be the actual master node. After resolution of this conflict the result is communicated by the prevailing master node to all nodes in the network. This resolution takes into account a global network with varying time zones, and further takes into account the remote possibility of a simultaneous appointment of two masters.

Claims

1. In a computer network having a plurality of nodes including a first master node and a second master node, a system for resolving conflict in said network between said first master node and said second master node comprising:

means for establishing a standard for comparison between said first master node and said second master node;

means for comparing said first master node against said second master node in accordance with said standard to obtain comparison results;

wherein said comparing means comprises;

means for choosing between said first master node and said second master node if said first master node and said second master node were selected simultaneously; and

,

means for determining which one of said first master node and said second master node was most recently selected to obtain a most recently selected master node if said first master node and said second master node were not selected simultaneously; and

,

means for selecting said master node from the group of nodes consisting of said first master node and said second master node based on said comparison results.

2. In a computer network having a plurality of nodes including a first master node and a second master node, a method for resolving conflict in said network between said first master node and said second master node comprising:

establishing a standard for comparison between said first master node and said second master node;

comparing said first master node against said second master node in accordance with said standard to obtain comparison results;

wherein said comparing comprises;

choosing between said first master node and said second master node if said first master node and said second master node were selected simultaneously; and

,

determining which one of said first master node and said second master node was most recently selected to obtain a most recently selected master node if said first master node and said second master node were not selected simultaneously; and

,

selecting said master node from the group of nodes consisting of said first master node and said second master node based on said comparison results.

3. A computer program product for use in a computer network having a plurality of nodes including a first master node and a second master node, said computer program product including a computer usable medium having computer readable program code thereon for resolving conflict in said network between said first master node and said second master node, said program code comprising:

program code for establishing a standard for comparison between said first master node and said second master node;

program code for comparing said first master node against said second master node in accordance with said standard to obtain comparison results;

wherein said comparing program code comprises;

program code for choosing between said first master node and said second master node if said first master node and said second master node were selected simultaneously; and

,

program code for determining which one of said first master node and said second master node was most recently selected to obtain a most recently selected master node if said first master node and said second master node were not selected simultaneously; and

,

program code for selecting said master node from the group of nodes consisting of said first master node and said second master node based on said comparison results.