HP OpenVMS Systems

Shared Memory (COMMONs) and Clusters?

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The Question is:

 
Installed image file section synchronization on a cluster.
 
I have an application that runs on both nodes in a cluster and expect to share
 data from an image section file installed from a cluster common disk. A
 $MGBLSC is issued when the image starts, and everytime a value is changed in
 the section, a $UPDSEC is i
ssued. The problem is that the values on each node appear to be independant of
 the other. Have I missed a basic concept? Am I allowed to use global sections
 this way?
 
Thanks in advance.
 
 

The Answer is :

 
  Neither global sections with backing storage nor commons are valid
  means to share memory across the members of a cluster.  These are
  node-local constructs.  (The OpenVMS Wizard will ignore the use
  of galactic sections for the purposes of this discussion.)
 
  The OpenVMS Wizard would strongly encourage use of standard RMS
  files, and with global buffers enabled.  By the time you complete
  your current approach -- particularly reflecting the necessary
  memory barriers, cluster-wide interlocks, and notifications --
  you will have (re)implemented RMS (with global buffers).
 
  Please see (2112), (2637), (2681), (7629) and particularly (6656).
 

  

     

     
answer written or last revised on ( 15-JAN-2003 )
     
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